Term
| role of vestibular system |
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Definition
| sensory system capable of influencing postural and movement mechnisms and will interact with other sensory systems at many levels of CNS |
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Term
| functions and components of vestibular system |
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Definition
| help maintain orientation in space keeps us aware of which way is up and where i am going; 1. utricular and accular maculae-primary organs for detecting position of the head with respect to gravitational force and linear acceleration in any plane and angular acceleration; 2. semicircular canals-serve as the primary organs for detecting angular acceleration in any plane (dynamic equilibrium) |
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Term
| rotation to the right reflexes |
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Definition
| 1. vestibuloocular reflex-eyes turn slowly in opposite direction to maintain visual contact with the environment and stabilize retinal image and as head turns farther and object moves out of the field eyes swing rapidly in direction of rotation to fix upon a new point (nystagmus) the direction of the nystagmus is given clinically as teh direction of the fast component and will develop reflexly during rotation with or without eyes open; 2. vertigo-during rotation the room appears to be turning to the left (objective vertigo; or subjective vertigo-subject feels he/she is turning to the right) and is sensation of rotation; 3. past pointing to the left-one were to reach out vertically to grasp an object while rotating the arm would have to diverge to the left to get it; 4. if standing, the subject would fall to the left |
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Term
| immediately after rotation to the right |
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Definition
| 1. nystagmus with slow component to the right; 2. room would appear to be rotating to the right; 3. past pointing to the right; 4. falling to the right; 5. deviation to the right on walking and turning to the right when stepping in place |
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Term
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Definition
| 1. nausea, increased salivation and vomiting; 2. sympathetics responses could increase such as pallor and cold sweat |
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Term
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Definition
| series of interconnected excavations within petrous portion of the temporal bone contains semicircular canal and a vestibule and contains perilymphatic fluid |
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Term
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Definition
| series of interconnected fibrous tube and sacs contained withing osseous labrynth always attached to osseous by one side and contains enolymphatic fluid |
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Term
| utricular and saccular maculae |
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Definition
| mostly horizontally oriented utricular macula patch of ciliated neuroepithelium and supportive cells located on the floow and anterior wall of the utricle and the cilia are imbedded in the overlying gelatinous otolithic membrane containing calcareous granules and this membrane has density greater than that of the endolymph and saccular macula is more verically oriented |
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Term
| oreintation of the semicircular canals |
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Definition
| 1. lateral canals-anterior end is ampullated and elevated 30 degrees above the horizontal plane and both ends open seperately into the utricle; 2. anterior/superior canal-plane at right angles to long axis of the petrous pyramid and ampullated anterior ends open seperately into the utricle and non ampullated posterior ends join the non-ampullated upper ends of the posterior canals to form a common canal which opens into the utricle; 3. posterior canals- parallel to long axis of the petrous pyramid and inferior ends of the post. canal ampullated and open separately into the utricle |
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Term
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Definition
| epithleium is thrown up into a ridge situatited transversely across the ampulla and epithelium is made of supporting cells and two varieties of ciliated neuroepithelial cells called hair cells and cilia of hair cells project into overlying gelatinous mass called the cupula which rises to the roof of the ampula and filling the part of ampulla not filled by the crista |
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Term
| ultrastructure of hair cells and innervation |
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Definition
| two distinct types of hair cells are innervated by afferent nerve terminals of peripheral process of bipolar cell of vestibular ganglion; efferent nerve supply; kinocilium one of the group of a bundle of cilia and the rest of them are sterocilia which get progressively taller in the direction of the kinocilium and these are regularly on the utricular side of the hair bundle in the lateral semicircular canals and on the canal side in the anterior and posterior canals; cells have a moderate level discharge rate and will increase rate when sterocilia are displaced toward the kinocilium and decrease their rate of discharge when sterocilia are moved away from the kinocilium |
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Term
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Definition
| hair cells in different regions of the utricular macula have their kinocilia placed on varying sides of their cilia tuft and located on the side of the hair cell tuft toward a curved axis called the stiola; so when gravity displaces otolithic membrane and will have hair cells bent in direction of kinocilia and increase rate of depolarization and other hair tufts are bent in the opposite direction and are hyperpolarized and the otolithic membrane is also displaced by inertial or momentum effects during linear and angular acceleration |
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Term
| effects of angular acceleration of head on vestibular apparatus |
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Definition
| at rest the cupula are undisplaced and there is resting frequency of discharge; at beginning of rotation of the head to the right-the walls of labyrinths move with the head and the endolymph lags behind and in the right SCC cause a relative endolymph flow from the canal toward the ampulla and displacing the cupula toward the utrice and causing a depolarization and in left lateral SCC the endolymph flows from the ampulla into the canal away from cupula and toward and cause hyperpolarization and decreased rate of firing and during rotation friction will cause endolymph to rotate at same angular velocity as the head and displacement ceases in about 3 seconds although it takes about 25-30 seconds for the cupula to return its resting position and will return to resting level |
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Term
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Definition
| if rotation to the right is abruptly terminated and endolymphatic will continue to be displaced in the direction of the previous rotation from appx 3 seconds and the cupula will remain displaced for about 25-30 seconds and will opposite of the rotation of the right and right SCC will be inhibited and the LCC will be depolarized and stiimulated; right vestibular dominance causes reflexes in response to stimulation that causes all reflexes to go to the left because the endolymph is going to the left and left vestibular dominance when stops and endolymph goes to the right and all reflexes going to the right |
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Term
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Definition
| those things that cause irritation of left labrynith of destruction of the right labyrinth and will produce a relative hyperactivity or dominance in left labyrinth also destructive lesions involving right vestibular nerve or vascular accident or tumor involving the right vestibular nuclei could produce signs of left vestibular dominance |
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Term
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Definition
| 1. right ear is irrigated with warm water and resulatnt warming of endolymph will cause it to rise towards the ampulla and stimulate right vestibular nerve and will generate all described reflexes; if irrigated with cold water will have endolymph move away from it and the imbalance between left and right will cause reflexes at the end of rotation making left more active than the right; if destructive disease present than the response will be diminshed and if irritative disease is present the responses will be exaggerated |
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Term
| functions of vertical canals |
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Definition
| have kinocilia on the side of the hair bundle away from the utricle and endolymph flow from the ampulla into the canal will stimulate their vestibular nerve branches; when head is tilted far foward; important is that vertica nystagmus is always a sign of central nervous system disease and usually brain stem nuclei that recieve primary projections of the anterior or posterior canals |
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Term
| anatomic pathways mediating reflex activities |
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Definition
| bipolar nerve cell bodies of the first neuron are located in the vestibular ganglion situated in internal audiotry meatus and send peripheral processes and most central processes terminated upon second order neurons in the specific ipsilateral vestibular nuclei and other pass into flocculonodular lobe and vermis areas of the cerebellum via inferior cerebellar peduncle |
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Term
| second order neurons of vestibular nuclei |
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Definition
| 1. inferior cerebellar peduncle largely ipsilatterally to flocculonodular and vermal regions of cerebellar cortex and fastigial nuclei for integration with all other sensory information; 2. cerebral cortex related to ascending trigeminal sensory pathways to contralateral cerebral cortex in the VP nculeus of the thalamus in region of face in the post central gyrus and posterior insular cortex and cortical area 7 in upper posterior parietal lobe important for aligning our body; 3. some direct projections to the abducens and other oculomotor nuclei through the MLF serve as primary pathway for producing the vestibuloocular reflexes and generates the slow phase of vestibular nystagmus |
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Term
| VOR and slow nystagmus to the right |
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Definition
| generated by fibers from the left vestibular nuceli which project to the right abducens nucleus to excite motor neurons of right lateral rectus and other internuclear neurons within the right abducens nucleus that prject across the midline at the level of the abducens nucleus to ascend the left MLF and end on the medial rectus portion of the left oculomotor nuclear complex and other vestibular nuclear fibers will enter the left paramedian pontine reticular formation and serves as part of the left horizontal gaze center and generate the fast component of the nystagmus to the left so patient in coma will only show the slow component of VOR because it involves the reticular formation |
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Term
| other projections of second order neurons of vestibular nuclei |
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Definition
| project via vestibulospinal tracts to excite MNs to ipsilateral antigravity muscles and what causes subjects to fall to the right to the right by the antigravity muscle thrust of the left lower limb and causes deviation to the right on walking and turning to the right on stepping in place; projections into reticular formation which directly autonomic systems including sensory and dorsal motor nuclei of vagus-nausea and vomiting, superior and inferior salivatory nuclei-increased salivation and reticulospinal and other autonomic pathways to the intermediolateral cell column-pallor and cold sweat; vestibular efferents-onto end organ afferents and hair cells and vestibular suppression may be mediated over these vestibular efferents which are felt to be largely inhibitory also may occur at higher levels of the vestibular system |
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Term
| other inputs of vestibular nuclei |
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Definition
| 1. vestibulocerebellum; 2. visual inputs demonstrated by motion sickness and mismatch between vestibular and visual perception can be improved by match the vestibular and visual perception; convergence of multiple sensory inputs on cells of the vestibular nuclei probably allows the vestibular nuclei to begin to correlate these inputs into unified concept of the spatial orientation but reaches highest level of appreciation at cerebral cortical levels |
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Term
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Definition
| 1. conjugate eye movements-both eyes move together in the same direction with the same velocity so visual axes remain parallel; saccadic eye movemetns-rapidly shift the fovea from one visual target to another; pursuit eye movemnts which slowly follow moving objects to keep the image of the target on the fovea; 2. vergence or disconjugate eye movements-two eyes move in opposite directions as in convergence or divergence |
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Term
| oculomotor nuclear complex |
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Definition
| located at high midbrain levels and located at the superior colliculus level immediately anterior to the periaqueductal gray area form a v shaped configuration and each of the five skeletal muscles has identifible cells columns within the ventrolateral somatic motor portion (levator palpebrae superioris, superior rectus, inferior rectus, inferior oblique, and medial rectus) and dorsalmedial part is the Edinger-Westphal nucleus that contains preganglionic parasympathetic neurons and root fibers of complex course ventrally through the red nucleus, medial aspect of substania nigra and then emerge from the interpenduncular fossa just medial to the crus cerebri |
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Term
| lower motor neuron lesion of oculomotor nerve |
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Definition
| produce ipsilateral 1. horizontal diplopia with external strabismus because of unopposed pull of the lateral rectus; 2. ptosis-because of loss of the levator palpebrae superioris; 3. loss of accomodation and fixed dilated pupil; 4. and if root fibers are injured while coursing through red nucleus there will be associated contralateral cerebral findings and if injured within substantia nigra will be associated contralateral basal ganglia findings and superior alternating hemiparesis if injured in the crus cerebri |
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Term
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Definition
| located at low midbrain level situated just anterior to the PAG at the level of inferior colliculus and indents the dorsal aspect of MLF innervates the superior oblique muscle; root fibers pass dorsally around the PAG and totall decussate dorsal to the PAG to form contralateral trochlear nerve and emerges at the pons midbran junction just below the inferior colliculus; trochlear nerve injury causes vertical diplopia on downgaze because loss of ipsilateral superior oblique and nuclear lesion the downgaze weakness will involve the ey contralateral to the lesion |
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Term
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Definition
| located in the low pons in dorsal part of the tegmentum in the floor of 4th ventricle and just lateral to MLF and has the facial motor root coursing superiorly along its medial border and looping over its rostral end; in LMN lesion causes ipsilateral loss of lateral rectus results in diplopia with the ipsilateral eye in internal stabismus; lesions of nucleus typically involve genu of the motor root of facial nerve to cause ipsilateral facial palsy and can involve closely related ipsilateral horizontal conjugate gaze center to also compromize conjugate gaze to the ipsilateral side and lesions of root fibers in pons base can cause contralateral hemiparesis called a middle alternating hemiparesis |
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Term
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Definition
| very rapid conjugate eye movements which shift the fovea from one visual target to another; reading a page of text, scanning a picture of persons face; fast phases of vestibular and optokinetic nystagmus and the rapid eye movements that occur during sleep; these are ballistic and once initiated there is no mechanism for adjusting their size or direction if target moves hten a second saccade must be made to correct the error; controlled by reticular formation gaze centers bilateral horizontal and vertical gaze centers and these are controlled by the superior colliculus and the frontal eye fields |
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Term
| bilateral horizontal conjugate gaze centers |
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Definition
| located in the paramedian pontine reticular formation- just ventral and rostral to the abducens nuclei and each produces horizaontal conjugate gaze to ipsilateral side; right PPRF produces right conjugate gaze by excitatory neurons to the LMNs of the right abducen nucleus-right lateral rectus and contain internuclear neurons which send their axons across the midline at low pons to enter the left MLF and ascend terminate and excite medial rectus subnucleus of left oculomotor nucleus; lesions of one PPRF will cause loss of all saccades to the ipsilateral side; damage to the MLF between the abducens and oculomotor nuclei will produce an internuclear ophthalmoplegia if on left MLF then right eye will move and left eye will not follow |
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Term
| vetical conjugate gaze center |
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Definition
| located in the reticular formation at the midbrain-diencephalon junction within and near the MLF; rostral intersitial nucleus of the MLF and located between the fibers of the rostral MLF and nucleus of each side projects to the vertical eye movement subnuclei of the right and left oculomotor and trochlear nuclei to cause bilateral upgaze or downgaze and lesions which cause loss of upgaze or downgaze must involve the riMLF bilaterally |
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Term
| supranuclear control of the saccadic conjugate gaze centers |
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Definition
| controlled mostly through superior colliculus and the frontal eye fields and stimulation of either area produces sccadic eye movements to the contralateral side; superior colliculus produces primarily reflex saccades in response to visual, auditory or somatosensory stimuli from the opposite side and projects to contralateral PPRF through decussation in the low midbrain; FEFs located in the posterior portion of the middle frontal gyrus and mostly control voluntary and memory guided saccades to the opposite side by projecting directly to the contrallateral PPRF or by projecting to the ipsilateral superior colliculus; unilateral destuctive lesions involving either of these produces a temporary disruption of saccades away from the side of the lesion and deviation of both eyes toward the side of the lesion but either area can compensate for the loss of the other and if both are damaged then there is permanent loss |
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Term
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Definition
| relatively slow tracking movements that allow the fovea to remain fixed on the moving object; vestibuloocular reflex and the slow phases of vestibular and optkinetic nystagmus are also pursuit movements; the occipital, temporal, and parietal multimodal association cortices involved in the where stream of vision are necessary to determine the direction and velocity of moving targets in order to matach eye movement direction and velocity to that target; these project to FEFs via long association pathways and by path that follow optic radiations back to the brain stem to end in the ipsilateral PPRF and abducens nucleus to cause ipsilateral pursuit eye movements; lesions in these cortical areas can compromise ipsilateral pursuit movements to side of the lesion |
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Term
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Definition
| occur when eyes converge to view a nearer object or diverge to view a more distant object; uses retinal disparity; some cells in visual cortex are sensitive to retinal disparity and project back to the midbrain and terminate on a vergence center in the upper midbrain reticular formation and projections to appropriate parts of the oculomotor and abducens nuclei to produce divergence or convergence (association with the near reflex |
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Term
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Definition
| focus our eyes from a distant to a near object and 1. both eyes converge to direct fovea on the new target; 2. both eyes ciliary muscles contract to allow the lenses to round up of their intrinsic elasticity to increase their refractive index; 3. both pupils constrict to increase the depth of field and sharpness of the image; involves the visual sensory pathway projecting through the visual cortices and visual cortices that detect disparity project into the midbrain along the optic radiations to terminate on the edinger-westphal nucleus and convergence center of the midbrain reticular formation |
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Term
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Definition
| each SCC is yoked through the vestibular nuclei and appropriate ocular motor nuclei to extraocular muscle pairs that will produce compensatory pursuit eye movements in a direction opposite the head movements that stimulate that canal serves as slow phase of a vestibularily induced nystagmus |
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Term
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Definition
| normally occuring reflex driven by movements of the visual scene relative to the body; afferent limb is the visual pathway projecting through the vsiual cortices to the pursuit center of the magnocellular stream then the pursuit pathway generates the ipsilateral pursuit movements and pursuit center will also projects via long association paths to the ipsilateral FEF which will generate the saccades to the opposite side; in left homonymous hemianopia a loss of optokinetic nystagmus moving to the side of the lesion can help differentiate an optic radiation lesion from other lesions behind the chiasm that can produce that vsiual field defects |
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Term
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Definition
| pinna, irregular shaped plate of elastic cartilage covered by thin skin (keratinized) and connective tissue |
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Term
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Definition
| outermost segment contains elastic cartilage which is continuous with the auricle and lined by thin skin with modified sweat glands, hairs and sebaceous glands (ceruminous) |
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Term
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Definition
| portion facing the external auditory canal is lined by a thin epithelium attached to thin connective tissue and epithelial lining the tympanic cavity |
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Term
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Definition
| air filled space in temporal bone containing three bony ossicles which is lined by ciliated columnar to simple squamous epithelium; ossicles-malleus, incus, and stapes are compact bone and transmit and amplify movements of tympanic membrane to the perilymph of the inner ear via oval window |
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Term
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Definition
| supported by bone, cartilage and connective tissue and connects tympanic cavity with the nasoparynx and acts to equalize air pressue in the middle ear cavity with the outside as well as provide a drainage route to the nasopharynx |
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Term
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Definition
| 1. transforms sound vibrations into neural signals that are conducted into the brain by way of the cochlear portion of the 8th nerve; 2. registers static and dynamic information about head position and sends it into the brain via the vestibular portion of the 8th cranial nerve |
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Term
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Definition
| interconnected series of tunnels attached to a central chamber within the petrous portion of the temporal bone and it is filled with connective tissue and perilymph which support the membranous labyrinth |
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Term
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Definition
| central chamber with extensions and lateral wall has an opening called the oval window to which attaches the stapes footplate and within these are utricle and saccle |
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Term
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Definition
| portion of bony labrynth is a tunnel that spiral 2 and 3/4 turns around a central body axis called the modiolus; the cochlear duct (scala media) connected to the saccule in the vestibule and ends blindly at the conchlear apex and this duct contains endolymph; one side of duct faces the scala vestibuli that is continuous at the apex of the spiral with the scala tympani and descends the cochlear spiral adajacent to the cochlear duct on the side opposite the scala vestibuli and ends as the round window facing the middle ear cavity |
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Term
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Definition
| CT supported tubes are lined mostly by a simple squamous epithelium and in certain areas it is highly modified for sensory reception, fluid secretion and absorption of endolymph in the conchlear duct is organ of Corti and functions in hearing |
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Term
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Definition
| endolymphatic fluid secretion areas in the lateral wall of the cochlear duct and the edges of the crista ampullaris in the SCC |
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Term
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Definition
| scala media triangular membranous tube that lies in the spiraling osseous tunnel of the cochlea and ends blindly at the helicotrema; has three walls basilar membrane, vestibular membrane and outer wall stria vascularis and lies in the mid part of each turn; above duct is scala vestibuli and below is scala tympani and these join at the helicotrema they contain perilymphatic fluid and lined by simple squamous epithelium and cochlear duct contains endolymph which is confluent with utricle, saccule and SCC |
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Term
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Definition
| specialized epithelial structure that tranduces sound energy to nerve impulses by inner and outer hair cells and only have modified microvilli and overlying the hair cells is a hinged structure the tectorial membrane that can make contact with the hair cells and bending of microvilli of the hair cells can be caused by oscillatory movements of the basement membrane and these movements indirectly activate nerve fiber endings at the base of these cells which are distal parts of the biplar sensory neurons located in the spiral ganglion in the modiolus and their central processes go to the brain via the cochlear division of the 8th nerve also has efferent axons that end on the hair cells and modulate their receptor activity |
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Term
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Definition
| encoded along the spiraling length of the cochlear duct with the high frequencies heard at the base and low frequencies at the apex so width and stiffness change so that different segments of basilar membrane oscillate in resonance with various frequencies |
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Term
| differences between endolymphatic fluid and perilymphatic fluid |
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Definition
| endo has higher K+ concentration so K+ rushes in when tectorial membrane is displaced and causes release of NTs onto the afferent nerve fibers and send signal transmission and in peri fluid has higher amount of Na |
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Term
| ventral and dorsal cochlear nuclei |
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Definition
| contain the second major neurons in auditory pathway and draped around the inferior cerebellar peduncle and axons from these neurons enter the lateral lemniscus both ipsilaterally and contralaterally so that from this point on auditory information entering from one ear ascends on both sides of the brainstem and some axons from cochlear nuclei and project up to the superior olivary nuclear complex |
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Term
| superior olivary nuclear complex |
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Definition
| located in the pons dorsal to the lateral aspect of the medial lemniscus; some neurons project axons to both lateral lemnisci; some neurons project axons to both facial motor and trigeminal motor nuclei for tensor tympani and stapedius and dampens transmission of sound vibration through middle ear ossicles; some axons project axons to hair cells of the organ of Corti to modulate receptor sensitivity; and receive sound information from both ear and can mointor and compare arrival times and intensities to provide cues for localization of sounds |
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Term
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Definition
| when chronic ear infections have hard time equalizing pressures and outside has greater pressure and falls in and indents and the cells degenerate and enzymes are released to perforate the tympanic membrane and if CT is used the epithelium will regenerate itself |
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Term
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Definition
| joints between bones become less moveable |
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Term
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Definition
| causes vertigo, tinnitus, hearing loss with abnormal Na in endolymph so have Na restrictions and diruretics and vestibular depressent |
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Term
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Definition
| axons arise from the cochlear nuclei, superior olivary complex and scattered neurons along its course through the membrane and majority fibers terminate in the nucleus |
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Term
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Definition
| serves as relay nuclei for audiotory information as well as reflex centers for motor responses of eyes, head, trunk, and limbs to auditory stimuli and there is a commissure where there is another opportunity for auditory info to cross; reflex center by projections to the superior colliculus and prjects to motor centers of the brain and spinal cord and direct reflex movements of the eyes, head, trunk, and limbs in response to sound; relay center-neurons project axons into the brachium of the inferior colliculus to terminate in the medial geniculate body |
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Term
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Definition
| neurons represent a part of the thalamic relay nuclei and axons from here from auditory radiations which terminate in the primary auditory cortex; receive info on intensity, timing and frequency of sounds from both eyes, recognition which is essential for processing speech; some neurons project to associational cortices for higher level processing of auditory information |
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Term
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Definition
| located within the transverese temporal gyri on superior aspect of the temporal lobe and there is tonotopic organization of neurons within auditory cortex |
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Term
| secondary auditory cortex |
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Definition
| found on the superior surface of the superior temporal gyrus extending onto the lateral aspect receives input from the primary audiotry cortex, integrative nuclei of the thalamus and medial geniculate nucleus; functions in identification of complex auditory sequences |
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Term
| heteromodal associational cortex |
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Definition
| recieve input from the unimodal association cortex of various sensory modalities, on posterior portion of the superior temporal grus is Wernickes area it is important for interpretation of the auditory information |
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Term
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Definition
| some parts of the adult human brain and can generate new neurons; can make identical copies of themselves for long periods of time and second they can give rise to mature cell types that have specific morphologies and specialized function usually form precursors prior to fully differentiated state but are committed |
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Term
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Definition
| confined space, physical contact of the cells with molecules on neighboring cells or surfaces and signaling interactions at the interface of stem cells and niches or descendent cells; paracrine and endocrine signals from local or distant sources; neural input and metabolic products of tissue activity |
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Term
| locations of niches in CNS |
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Definition
| 1. sub ventricular zone and in adult it is much smaller; 2. in mice in streak of tissue that connects the lateral ventricle and the olfactory bulb and constantly being regenerated; 3. hippocampus and play role in certain kinds of memory; 4. exernal granular layer of cerebellum can undergo malignant transformation possibility |
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Term
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Definition
| isolated stem cells from CNS and differentiated into neurons, astrocytes, and oligodendrocytes in culture and when injected into the brains of immunosuppresed rats the cells differentiated into neuron like functional cells and glial cells |
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Term
| gene therapy and stem cells |
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Definition
| take cDNA of gene and clone into viral vector and infect tissue but individual may undergo strong immune response and virus can not work; stem cells can circumvent this problem propagate in vitro and then inject into stem cell and protein of interest will be secreted and minimalize negative effect of immune system |
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Term
| culture of neuroblast progenitors |
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Definition
| have neuroblast medium-AAs, vitamins, Glutamate, glucose; have insulin supplement and growth factors EGF and bFGF |
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Term
| MAPK pathway in neural progenitor |
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Definition
| tyrosine kinases and recruit signalling molecules to MAPKinase (Ras-MAPK) and become serine theronine kinase to phosphorylate TFs in nucleus; when this pathway is modified and cells become differentiated |
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Term
| insulin signaling pathway |
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Definition
| has weak and strong activation pathways the weak one is Ras-MAPK and strong pathway IRS1 to recruit GLUT4 so cells can import glucose because neurons like glycolysis for ATP |
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Term
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Definition
| the excess insulin activates this which involved in proliferation and protection of apoptosis and may induce differentiation including neural differentiation and also may facilitate cellular transformation by viral oncoproteins including JCV T antigen |
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Term
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Definition
| brains are underdeveloped and low level of survivin to protect cells from spontaneous apoptosis but in optimal culture conditions there is only a slight difference but when challenged by JCV T antigen (transformer protein of pRb and p53) it kills all neural progenitors that do not express IGF-IR but can rescue these cells with survivan which requires the presence of IGF1; expression of JCV T antigen with IGF 1R leads to the development of cerebellar tumors which originate from neuronal progenitors |
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Term
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Definition
| 1. growth factors; 2. cell-to-cell interactions; 3. birthday of the cell; these factors determine how neurons develop in different regions of the nervous system |
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Term
| paths of neuroepithelial cells |
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Definition
| choose whether to go towards neuron or glial cell and then once starts to differentiate toward becoming a glial cell than one can influence another and oligodendrocytes differentiates under influence of astrocytes |
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Term
| neurotrophic factors important in development of neurons |
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Definition
| regulate survival of neurons; nerve growth factor, brain derived neurotrophic factor and neurotrophi-3 all support different types of neurons also require other types of factors including laminin |
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Term
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Definition
| default pathway and path the cell takes without appropriate stimulation from appropriate growth factors |
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Term
| neural crest cells and local environment |
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Definition
| plays a role in type of transmitter that a neuron synthesizes; either norepinephrine or acetylcholine |
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Term
| interaction between neurons |
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Definition
| lead to specific differentiation of different cell types ie in drosophila eye development have units that have 8 specific specialized receptor neuron types |
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Term
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Definition
| cells produce ligands like R7 that produces ligand controlled by the sevenless gene and if not expressed then R7 will not develop and the R8 boss gene and encodes the receptor for the R7 ligand and there is an interaction between the ligand and the receptor which is necessary for differentiation and survival of R7 cell and this cell to cell interaction that occurs spatially and temporally |
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Term
| interaction between glial cells and neuroblasts |
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Definition
| in cerebellum neurons must migrate from deep cerebellum to the cortex and in mutant mouse weaver and granule cells normally located in cortex do not reach there and do not migrate to adult location because of defect preventing granule cells from interacting with glial cells |
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Term
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Definition
| day the cell stops dividing and the neuron becomes postmitotic; in cerebral cortex the first set of neurons that stop dividing populate the deeper cortical layers and neurons that stop dividing later will migrate over the deeper neurons and will lie more superficial so commitment of the neuron to stop dividing is more important than actual migration of the neuron and path of migration |
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Term
| factors determining axonal guidance |
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Definition
| 1. cell surface markers; 2. extracellular matrix molecules |
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Term
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Definition
| specialized tips of growing axons that organized into filopodia and extend from the growth cone and can respond to local cues to move in particular direction or change direction; integrins are found on these and can interact with laminin or fibronectin and also cones have cadherins and interact with cells the cone comes in contact with |
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Term
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Definition
| include netrins molecules act to attract growth cones to a target can attract some and repel others; other molecules like NgCAM promote the elongation of axons that migrate along the astrocytes and schwann cells and NCAM allows neurons to attach to each other |
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Term
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Definition
| if limb bud in chick is removed then without the developing limb there is a reduction in number of anterior horn cells |
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Term
| consolidation and maturation of neural connections |
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Definition
| unused synapses become nonfunctional and receptor is eliminated as the axon is withdrawn but one synapse must remain active for this pruning to occur; also requirement for an interaction betweeen the organism and the environement so that the sensory circuits that have been established become refined and these are called critical periods of development (for language and many other things) |
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Term
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Definition
| disruption of the blood supply to particular area of the brain and usually manifest in alteration in behavior |
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Term
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Definition
| cant smell and infertile from olfactory placode that gives rise to olfactory receptor neurons and GnRH cells migrate together |
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Term
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Definition
| hypertension, diabetes, smoking, hyperlipidemia, advanced age and male gender |
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Term
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Definition
| 1. vasculopathy-ischemia and end organ damage; 2. heart disease-pump problem; 3. coagulapathy-problem with blood |
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Term
| environmental risk factors |
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Definition
| 1. smoking-causing microvessel damage; 2. cocaine use- increases blood pressure, vasopasm and immune mediated vasculitis; 3.IV drug use-dump bacteria in veins or arteries; 4. diet |
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Term
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Definition
| 60-90 seconds lack of ATP from Krebs cycle; necrotic cell death 5 min to 3 hours and after 3 hours can not rescue; have apoptotic cell death for months |
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Term
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Definition
| release of the NT from the presynaptic nerve will increase the chances of an action potential in the postsynaptic cell |
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Term
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Definition
| release of the NT from the presynaptic nerve will decrease the chances of an action potential |
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Term
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Definition
| usually G protein coupled receptors, use signal transduction pathways and an ion channel may or may not be involved but its not part of the receptor |
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Term
| rules of excitatory vs inhibitory |
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Definition
| threshold for action potential generation of most nerves is about -50mv; if reversal potential of a receptor is above -50mV then opening that channel will increase the chances of an action potential and is excitatory; if reversal potential is below -50mV then opening that channel will decrease the chances of an action potential and the NT that binds to the receptor is inhibitory |
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Term
| function of metabotrophic receptors |
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Definition
| 1. some receptors are directly coupled to ion channels by G-proteins; 2. in other cases the action of receptors is less direct and changes are caused by second messangers generated by NT binding; 3. usually causes effects that are slower and longer lasting than those caused by ionotrophic receptors (more likely to be modulatory than transmitting info itself); 4. autoreceptors-found on presynaptic terminals and they bind some NT that is released by the nerve and allows the nerves to regulate itself-often inhibits release and may inhibit NT synthesis |
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Term
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Definition
| 1. glutamate-most widespread excitatory NT in CNS; 2. ACh-used in preganglionic fibers in parasympathetic and sympathetic and parasympathetic postganglionic; 3. norepinephrine-used by postganglionic fibers of sympathetics and also in the CNS; 4. serotonin; 5. dopamine-role in basal ganglia and skeletal motor system; 6. GABA-widespread inhibitory neurotransmitter in CNS; 7. glycine-inhibitory NT in the spinal cord; 8. peptides (enkephalins, substance P, somatostain, and VIP); 9. NO-crosses membrane and has intracellular effects |
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Term
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Definition
| synthesized by acetly coenzyme A and choline; choline is made from serine and pumped into the nerve terminal by a sodium secondary active transport system; choline acetyltransferase is synthesized in the cell body and transported to the nerve terminal by axonal transport |
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Term
| amino acids and derivatives |
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Definition
| glutamate is excitatory NT; GABA is formed when one of the COOH groups of glutamic acid is removed by glutamic acid decarboxylase and only found in neurons that secrete GABA; glycine is also inhibitory and is an amino acid |
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Term
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Definition
| tyrosine is a precursor for dopamine, norepinephrine and epinephrine; add a OH group to tyrosine make L-DOPA and this is decarboxylated by dopa debycarboxylase to make dopamine; and if expresses dopamine b-hydroxylase the dopamine will be converted to norepiephrine ad chromaffin cells of medulla has enzyme to methylate norepinephrine to make epinephrine |
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Term
|
Definition
| tryptophan is hydroxylated and then a COOH is removed to make serotonin |
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Term
|
Definition
| produced by the action of histidine decarboxylase on the amino acid histidine |
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Term
|
Definition
| made in cell body and stored in vesicles and vesicles are moved to the nerve terminal by axonal transport |
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Term
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Definition
| inactivated by actylcholinesterase present in the synaptic cleft; choline and acetate are produced and choline is transported back in the presynaptic cell by the Na dependent mechanism and inhibitors of this enzyme are used to treat myasthenia gravis |
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Term
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Definition
| removed by synaptic celft by reuptake into the presynaptic cell of glial cells and diffusion away from the cleft; drugs act by interfering with the reuptake process (prozac-serotonin); biogenic amines are inactivated by COMT and MAO with MAO in the presynaptic nerve terminal and COMT in other tissues and endothelial cells |
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Term
| excitatory postsynaptic processes and summation |
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Definition
| glutamate or substance P binds to receptors on a-motorneuron in the spinal cord it causes the opening of the ionic channels permeable to Na and K; each presynaptic nerve terminal releases only a few vesicles so EPSP is smaller than the NMJ; spatial summation-occurs by firing of many presynaptic cells and these summate with each other; temporal summation occurs by repetitive firing of a single presynaptic cell |
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Term
| changes after repetitive stimulation |
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Definition
| can change the amount of NT released at a synapse; fatigue or depression can occur when the presynaptic cell releases NT faster than it can transport or synthesize and repackage NT into vesicles; less NT release with each AP (presynaptic phenomenon) |
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Term
| facilitation and post-tetanic potentiation |
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Definition
| pre-synaptic phenomena where more neurotransmitter than normal is released in response to a presynaptic AP; both occur because the intracellular Ca concentration in nerve ending is slighlty elevated above resting levels and more Ca means more NT release |
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Term
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Definition
| threshold is lower at the axon hillock than on the cell body; EPSPs produced at dendrites travel to the cell body but get smaller in magnitude as they because the mechanism is electrotonic conduction; IPSPs may also be produced on dendrites and travel to the cell body; and both will summate at the cell body |
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Term
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Definition
| ionotropic glutamate receptor; widely distributed in the CNS esp in cortical and hippocampal regions and generates slow EPSPs allows NA, K, and Ca to pass through it |
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Term
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Definition
| aka quisqualate receptor and have parallel distribution with NMDA receptors; generates fast EPSPs |
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Term
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Definition
| receptors are concentrated in a few specific areas of the CNS and will be permeable to Na and K |
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Term
| action of NMDA glutamate receptor |
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Definition
| part of an ionic channel and activation causes a conductance increases Na, K, and Ca ions and its response is depolarizing and slow; ketamine and PCP and Mg block NMDA receptors by binding to the ion channel; when glutamate bind the receptor the channel opens and immediately blocked by Mg from the outside; the Mg block is voltage dependent; when Em is depolarized to about -40mV Mg moves outward; this will be removed if glutamate binds enough AMPA receptors to depolarize the cells enough or when an action potential in the postsynaptic cell propogates back to the NMDA synapse and Ca will be able to enter; these receptors can increase intracellular Ca but chronic activation can cause cytotoxic effects and lead to neuronal death because of too much Ca; glycine modulates allosterically and binds and allows more current to flow through the channel |
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Term
| action of kainate and quisqualate |
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Definition
| ionic channels permeable to Na and K but impearmeable to Ca and MG does not block these channels |
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Term
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Definition
| can increase the excitatory inout or decrease the inhibitory input which is what disinhibition is |
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Term
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Definition
| important inhibitory in the spinal cord and opens selective Cl channels and the Em is less than -50mV this is inhibitory |
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Term
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Definition
| inhibitory NT in the CNS; subtype A are ionotropic found on all CNS neurons and it opens Cl selective cahnnels and this response is enhanced by diazepam or barbiturates; B subtypes receptors a metabotropic receptors that cause hyperpolarization by increasing K conductance or decreasing Ca conducatance and both can be involved in presynaptic inhibition |
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Term
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Definition
| way to lessen the response to one specific input without decreasing sensitivity in general; an axon synapses on another axon (axoaxonic synapse) and if inhibitory NT is released at the synpase of the axon the nerve ending will release less transmitter; GABAb on presynaptic nerve terminals can modulate transmitter release and binding increases K conductance and decreasing Ca and having less Ca enter the cell and less NT released this allows the input to be modulated without affecting the overal excitability of the cell |
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Term
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Definition
| are activated by muscarine and inhibited by atropine and there are five types M1-M5 and the are coupled to different Gproteins Gi and Gq; the open channels that are not part of the receptor either directly through G protein interaction or indirectly through 2nd messangers; M2 receptors in the atria are linked to K channels by a G protein and the beta gamma subunit interacts with K channel and increases it conductance; M3 receptors activate PLC which produces IP3 and DAG |
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Term
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Definition
| divided into alpha and beta with two subtypes; alpha1-causes activation of PLC; and the other types either activate or inhibit adenylyl cyclase and production of cAMP; B1 and B2 activate AC which increases cAMP which activates PKA; and A2 receptor causes the activation of Gi protein which causes the inhibition of AC |
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Term
|
Definition
| five types D1 to D5 all metabotropic and modulatory and D1 and D5 are coupled to Gs and are generally excitatory increasing cAMP and PKA and affects some ion channels; D2-D4 are coupled to Gi and are generally inhibitory |
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Term
| components of the basal ganglia |
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Definition
| consist of the caudate, putamen, globus pallidus, nucleas accumbens, ventral pallidum, amygdala, subthalamic nucleus and substantia nigra |
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Term
| functions of the basal ganglia |
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Definition
| 3 subdivisions including skeletal motor, associative (cognitive) and limbic (emotional); major inputs to the basal ganglia are from cerebral cortex to the caudate, putamen, or nuc accumbens; caudate and putamen then project to the the globus pallidus and nuc accumbens project to ventral pallidum then project to specific nuclei |
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Term
| skeletal motor subdivision and circuit |
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Definition
| inputs-to putamen principally from somesthetic and motor cortices; output-from globus pallidus to motor thalamus (VA+VL); VA and VL project to premotor and supplementary motor cortices; reinforce intended movements and suppress unintended movements which would interfere with the desired activity; lesions produce movement disorders |
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Term
| associative or cognitive subdivision and circuit |
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Definition
| inputs- to head of caudate from dorsolateral prefrontal cortex; output from the globus pallidus to mediodorsal and ventral anterior nuclei of thalamus and these project to the dorsolateral prefrontal cortex; focus cognitive processes necessary for executive attention and problem solving; reinforces attention focused on the task at hand and suppresses distraction by potentially irrelevant stimuli inputs; lesions cause attentional deficits |
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Term
| limbic/emotional subdivision and circuit |
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Definition
| inputs to nucleus accumbens and ventromedial caudate and putamen from orbital and medial portions of the prefrontal cortex and anterior cingulate gyrus; output from ventral pallidum to mediodorsal nucleus of thalamus and these porject back to prefrontal cortex and anterior cingulate gyrus; function in judgement and decision making required for choosing adaptive and appropriate behaviors anticipated reward values for behavioral choices and anterior cingulate specialized to evaluate the effort or cost of attaining rewards; lesions associated with irritability, emotional lability, inappropriate response to social cues, and poor decision making and tend to be driven by immediate rewards vs consideration of reward value and effort required to obtain the reward in the context of long term goals |
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Term
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Definition
| principal receptive component for the skeletal motor circuit and inputs are from ipsilateral cerebral cortex and lesser inputs are from ipsilateral thalamus, SN, and reticular formation and the cortical inputs are excitatory |
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Term
| globus pallidus internal segment |
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Definition
| outflow from basal ganglia and pars reticulata component of the substantia nigra and there is outflow to the ventral lateral and ventral anterior nuclei of the thalamus and project back to the motor cortical areas (premotor and supplementary) and VA, VL neurons use glutamate and are excitatory; the outflow of GPi and SNr use GABA and are tonically inhibitory of thalamus |
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Term
|
Definition
| GPi and SNr are tonically active and inhibitory to VA/VL and the putamen is transiently activated by cortical areas and these neurons transiently inhibit the output neurons of GPi and SNr which reduces the inhibitory effect on the thalamus allowing it to be become activated and exctie their cortical targets in motor association areas; disinhibition of VA/VL and this promotes movement, specifically of intended activities |
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Term
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Definition
| net effect of activation is to decrease thalamic and cortical activity and suppresses movement; STN uses glutamate as transmitter and provides excitatory drive to the GPi/SNr which increases inhibitory outflow to VA/VL; STN activity is modulated by GPe which uses GABA to tonically inhibit STN; when neurons in putamen are excited to indirect pathway they transiently inhibit the neurons in GPe thereby disinhibiting STN and this excites the GPi/SNr resulting in greater inhibition of thalamus and less excitation of motor cortical areas and generalized suppression of movements |
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Term
| dopaminergic inputs from the substantia nigra |
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Definition
| located in pars compacta division of SN (SNc) these neurons project to the putamen associated with both direct and indirect pathways; dopamine receptors differ on these neurons and is generally excitatory to direct pathway neurons and inhibitory to indirect pathway neurons; net effect is to promote movemnt by facilitating the direct pathway and suppressing the indirect pathway; inputs to the SNc include components of limbic system and prefrontal cortex tune the balance of activity in the direct and indirect pathways to specific select the cortical motor programs that will produce rewarding outcomes |
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Term
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Definition
| during normal movements; both the direct and indirect pathways are active; the indirect pathway is generalized and direct pathway is focused and overcome the generalized suppression of movement caused by indirect pathway and direct reinforces the motor programs that will best accomplish the intended movement activity while the activity generated in the indirect pathway suppresses all other movement activities (action selection) |
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Term
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Definition
| alters overall inhibitory drive that the basal ganglia exerts on the thalamus; greater GPi/SNr inhibtion of thalamus results in hypokinesia and less yields hyperkinesia and signs occur contralaterally because basal ganglia effects ipsilateral motor cortical areas |
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Term
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Definition
| significant reduction in movement activity and for voluntary movements undertaken there is a reduction in their amplitude and velocity (bradykinesia); underactivity of direct pathway and over activity in the indirect pathway |
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Term
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Definition
| show excessive motor activity in the form involuntary movements; uncontrollable and purposeless movements results in over activity in the direct pathway and/or underactivity in the indirect pathway |
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Term
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Definition
| cardinal signs include tremor, rigidity, akinesia, and postural instability (TRAP), and bradykinesia occur when 75% of dopaminergic neurons of the substantia nigra (SNc) have degenerated causing reduced excitation of the direct pathway and increased activity to the indirect pathway; lead pipe rigidity, flexed posture |
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Term
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Definition
| included enhancing dopamine transmission in surviving SNc neurons and deep brain stimulation; dopamine replacement therapy is effective symptomatically but in long term produces serious movemnt related side effects termed dyskinesias |
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Term
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Definition
| flailing or swinging movements of the limbs this can result from lesions of the contralateral subthalamic nucleus; lesioning the motor cortex or the corticospinal tract does stop it and reflects dysregulation of the corticospinal |
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Term
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Definition
| autosomal dominant neurodgenative disorder caused by a repeat expansion of huntingtin; symptoms include choreiform movements early in the disease progression and progressive behavioral and cognitive impairment; and movement disorder changes to that of dystonia or a PArkinsons disease type of rigidity and akinesia; neurodegeneration in cerebral cortex, cerebellum, and caudate and putamen (this degeneration is very striking and obvious early in disease progression) |
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Term
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Definition
| regulate coordination of muscle groups to maintain balance and perform skilled movements; enables us to learn to perform accurate and smooth movement, events at high speeds and without visual feedback |
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Term
| basic circuit for movement |
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Definition
| is the reflex and playing down on this spinal cord circuitry are descending pathways and the basal ganglia and cerebellum can modulate the unput into the spinal cord from higher levels |
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Term
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Definition
| 1. prefrontal cortex is involved in planning movements; 2. premotor cortex is involved in programming movements; 3. primary motor cortex then becomes active during the movement itself |
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Term
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Definition
| initial learning of movements begins under cortical control and cerebellum participates in controlling the task; it also comes to recognize the context for the movement and then links the requiste movements together and under the appropriate stimulus the movement is automatically triggered |
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Term
| cerebellum learning new movements |
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Definition
| takes learned movements and adapting them to new movements; it sequences complex movements automatically and unconsciously and sequences activation of muscles and prevents movement errors and these can involve actions across multiple joints |
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Term
|
Definition
| apprx 70% of neurons in the brain reside in the cerebellum and almost every sensory system provides input into the cerebellum; organized into three lobes; 1. flocculonodular lobe; 2. posterior lobe; 3. anterior lobe; anterior lobe is seperated from the posterior lobe by the primary fissure and posterior lobe seperated from the flocculonodular lobe by the posterolateral fissure |
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Term
| medial-lateral divisions of cerebellum |
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Definition
| vermis considered the most medial portion and then laterally would have the paravermis and the most lateral part is the lateral zone |
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Term
| functional subdivisions of cerebellum |
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Definition
| 1. part that interacts with vestibular system is called the vestibulocerebellum and consists of the flocculonodular lobe; spinocerebellum receives major input from ascending pathways from the spinal cord and predominant part involved is the anterior lobe and paravermis; cerebrocerebellum input from cerebral cortex and it involves the lateral cerebellar hemispheres |
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Term
|
Definition
| 1. vestibulocerebellum is the fastigal nucleus; 2. interposed nuclei are associated with spinocerebellum; 3. dentate nucleus associated with cerebrocerebellum and these provide excitatory output from the cerebellum with NT as Glutamate and fire at a rate of 40-50 resting so can be modulated up or down and result muscle tone at rest |
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Term
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Definition
| described as having three layers, the outer layer is the molecular layers; and the inner layer is the granule cell layer and in between in Purkinje cell layer; inputs to the cerebellum are from mossy fibers and climbing fibers; mossy fibers are excitatory and arise from all inputs into the cerebellum except from the inferior olive and synapse on granule cells and climbing fibers from contralateral inferior olive; these are excitatory to Purkinje cells and both mossy and climbing fibers are excitatory inputs to the deep cerebellar nuclei; granule cells synapse on parallel fibers providing excitatory input to Purkinje fibers and output from Purkinje cells is inhibitory and this output plays down on the deep cerebellar nuclei |
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Term
| vestibulocerebellum circuit |
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Definition
| acts ipsilateral and controls vestibular reflexes and maintains posture, blance and equilibrium and it is important in influencing the movement of eye muscles and works in conjugation with the vestigal nucleus; lesions present with ataxic gate and staggering and wide based walking; via ICP vestibular nuclei and vestibular end organ send to flocculonodular lobe which send to fastigal nucleus which go to vestibular nuclei to vestibulospinals and reticular formation for reticulospinals for control of head postion relative to the trunk |
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Term
|
Definition
| involves the anterior lobe of cerebellum and paravermis; receives input from spinal cord from spinocerebellar and cuneocerebellar pathways; it acts ipsilaterally and then to reticular formation; uses propriocetive inputs to modulate muscle tone and involved in coordinated movements of the limbs and is active during walking and in other stereotyped movements and also influences head movements |
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Term
| spinocerebellar inputs and outputs |
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Definition
| from nucleus dorsalis and accessory cuneate nucleus go through ICP to vermis and anterior lobe and synapse on interposed nucleus and exit through ICP to reticular formation and vestibular nucleus and through SCP to red nucleus and VL of thalamus to primary and premotor cortices; acts to control stretch, contact, placing and other refelxes; lesions would manifest themselves in postural reflexes; alcoholics abusing alcohol can destruct anterior cerebellar cortex resulting in gait ataxias |
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Term
|
Definition
| involves the lateral cerebellar hemispheres and input is from cortex via the pontine nucleus and acts ipsilaterally but pathways crosses twice; motor plans orginate in the cerebral cortex and send info to pontine nucleus and send projections across midline into the MCP and purkinje cells project to the dentate nucleus and these project to contralateral VL nucleus via dentatothalamic tract and to the red nucleus and VL projects to motor cortices and projections to red nucleus are relayed to inferior olive and reticulo(rubro)spinal tract; involved in coordinating the fine movements of the distal limb musculature and in motor planning in general |
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Term
| corticopontocerebellar axons |
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Definition
| sensory info about the movement is compared to the actual intended movement and comparison is done in cerebellum and during ballistic movements some of this info goes back to the cortex is based upon predictions from past experiences and cells in dentate can actually fire prior to the onser of a movement |
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Term
| lesions to cerebrocerebellum |
|
Definition
| asynergia-loss of coordination of motor movements; dysmetria-inability to judge distance and when to stop; adisdiaadochokinesia-inability to perform rapid alternating movements; intention tremor-occur while attempting to perform a movement; hypotonia; ataxia dysarthria; cerebellar nystagus |
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Term
|
Definition
| involved in motor learning receives inputs from red nucleus, dentate nucleus the spinal cord and cerebral cortex and superior colliculus; prjections from inferior olive reach cerebral cortex through climbing fibers and synapse on Purkinje ibers and this circuit is involoved in long term modifications in the output of the cerebellum as it adjusts sensory feedback about movements |
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Term
| other functions of the cerebellum |
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Definition
| sensory and cognitive tasks and emotional state of the individual; it was active during acquistion of thrist; actively involved in music |
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Term
|
Definition
| involves two important elements: first is the ability to stand need to get into an upright position, maintain that position and return to that position; locomotion needs to be initiated and then maintained with a patterned rhythmic series of movements; initiaton can be generated from different regions of the CNS |
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Term
|
Definition
| basic movements are generated at the level of the spinal cord and modifications of gait cycle are made in the brainstem and further modification and the acutalwilling of the action of locomotion is made at higher central nervous system levels |
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Term
|
Definition
| alternating of flexors and extensors during gait and when flexors are active then the extensors in the same limb have to be quiescent this can be generated in the spinal cord; interneurons that generate the flexor activity can inhibit the extensor activity in the same limb |
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Term
| function of sensory afferent |
|
Definition
| modify the stepping seen in gait; input from the vestibular system and the visual system can modify gait; vestibular system plays a very important role in gait by permitting humans to stand upright and then walk |
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Term
| mesencephalic locomotor region |
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Definition
| initiation of locomotion starts and would play down upon cells in the medullary reticular formation and reticulospinal pathways would influence the different generators in the spinal cord |
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Term
| cerebellar role in locomotion |
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Definition
| interplay between cerebellum and medullary reticular formation and has regulatory role through the reticulospinal pathways and permits the cerebellum to compare the proprioceptive information that is being generated with the intended movements and correct them |
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Term
|
Definition
| work to reinforce the intended gait movement and to eliminate any unintended movements and one of outputs of GPi is mesencephalic locomotor system |
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Term
|
Definition
| visual cues are used to modify gait and important in precision wlaking and plays a major role when it is critical to place feet accurately during gait |
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Term
|
Definition
| important in gait, bilateral lesion to SMA had clumsy gait and had difficulty initiating foot/leg movements |
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Term
|
Definition
| cell found in primary motor cortex can innervate several neurons that innervate more than one muscle |
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Term
|
Definition
| in monkeys in power precision grip and power grip activate the intrinsic hands of the muscles but the cortical areas involved in the precision grip are not active in the power grip and vice-versa |
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Term
| changing of motor cortex during learning and following injury |
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Definition
| in monkeys small area of PMC controlling hands and digits were destroyed and could not do fine motor skills and it was found that the cortical area was very reduced compared to non lesioned animals but if were retrained the cortical layers enlarged |
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Term
|
Definition
| subjects were asked to practice a task and using fMRI and those areas that were practiced were larger then the amount of cortex used in novel task; voluntary movements can improve with practice and the area of the cortex involved in a practiced activity expands with practice important in normal motor learning as well in rehabilitation of patients with cortical lesions |
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Term
| other changes in motor cortical areas |
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Definition
| active premotor cortex changes as the performance becomes automatic; supplementary cortex sets the motor programs for learned sequences |
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Term
|
Definition
| involves the supplementary motor cortex; in another aspect of cortical control, if movement is generated by an internal signal then the supplemental motor area is involved; if triggered by external signal then the lateral premotor area is involved and involved in learning to associate a motor activity with a sensory event |
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Term
|
Definition
| dorsal premotor area is involved in reaching and ventral premotor area is involved in grasping; spatial info goes to dorsal premotor (where pathway) and object recognition goes to ventral premotor (comes from what pathway) |
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Term
|
Definition
| refers to hypokinetic movement disorders |
|
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Term
|
Definition
| happen because of genetic and environemental factors causing apoptosis and the symptoms depends on where it starts with SN-Parkinson, hippocampus-Alzheimers. frontal lobe-Picks diease |
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|
Term
| Symptoms of Parkinson diease |
|
Definition
| 1. Tremor-usually in hands at rest with a frequency of 3-5; 2. Rigidity-cogwheeling; 3. akinesia and bradykinesia; 4. postural instability (slouching foward); shuffling of gait, no arm swinging, turning body is like a block, hypomimmia-face becomes masked, hypophonia-cannot project voice very well; micrographia-writing deteriotes and becomes small and shaking |
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Term
| causes of cell death in the SN |
|
Definition
| infections, toxins, drugs, trauma, stroke, smoking; also genetic factors |
|
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Term
| function of the hypothalamus |
|
Definition
| maintain physiological homeostasis, to regulate the internal environment of the body within a narrow pysiological range in response to changing external environment |
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|
Term
| nucleus of solitary tract |
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Definition
| where hypothalamus receives visceral sensory input; the hypothalamus also receives input from the periphery and cortical and limbic projections |
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Term
|
Definition
| controls the autonomic nervous system to act on internal organs, blood vessels and glands, producing physiological and behavioral effects; also controls motivated behaviors like food intake; critical role for the hypothalamus is in the regulation of rhythmic hormonal output and rhythmic behaviors such as sleep wake cycle |
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Term
| major divisions of hypothalamus |
|
Definition
| 1. anterior-landmark is the optic chiasm contains the paraventricular nucleus, suprachiasmatic nucleus, supraoptic nucleus, and preoptic nuclei; 2. middle-between anterior and posterior hypothalamus contains the arcuate and ventromedial nuclei; 3. posterior- landmark in mammillary bodies; also divided into a medial and lateral divisions with the fornix as a landmark seperating the two divisions |
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Term
|
Definition
| specialized brain regions with access to blood borne chemicals because they lack blood brain barrier; subfornical organ stimulates magnocellular hypothalamic neurons to release vasopressin and lateral hypothalamus to stimulate thirst and drinking; magnocellular cells in PVN of hypothalamus release vasopressin |
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Term
| parvo neurosecretory cells |
|
Definition
| in the anterior pituitary project to the median eminence at base of hypothalamus and release hypophysiotropic hormones into the hypothalamo-pituitary portal circulation |
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Term
|
Definition
| releasing hormone is unknown and inhibited by dopamine, and the target is mammary glands |
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Term
|
Definition
| two main divisions are the sympathetic and parasympathetic nervous systems; most target organs are dually innervated and others are activated only by one |
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Term
|
Definition
| hypothalamus controls the ANS via descending autonomics with pass through the lateral aspect of the tegmentum at midbrain and pons levels through the lateral aspect of the medulla and are found in lateral funiculus of the spinal cord and project to PAG, cardiovascular and respiratory centers in pons and medulla, dorsal motor nucleus and nucleus ambiguus in medulla; intermediolateral cell column located at T1-L2 and S2-S4 (parasympathetics) |
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Term
|
Definition
| receives input from sensory cortex about the external world and allowins the ANS to be controlled by internal states or external events |
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|
Term
| sympathetic nervous system |
|
Definition
| preganglionic neuron cell bodies located in the thoracic and lumbar spinal cord and exit spinal cord to synapse on postganglionic neurons in the sympathetic chain; preganglionic neurons release ACh acts on nicotinic Ach receptors; and postganglionic release norepinephrine system for widespread effects; sympathomimetic are drugs that stimulate norepinenphrine and those that inhibit are parasympathomimetic |
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Term
| parasympathetic nervous system |
|
Definition
| located in the brainstem or scaral spinal cord synapse on postganglionic cells in autonomic ganglia at or near target organ; release ACh which acts on nicotinic Ach receptors and postganglionic cells also release ACh which acts locally to stimulate muscarinic Ach receptors on target organs; facilitate digestion, growth, immune response, energy storage |
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Term
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Definition
| elicited by perturbations to the function of ANS targets; and sympathetics and parasympathetic reciprocally engaged to restore homeostatsis |
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Term
| baroreflex to maintain BP |
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Definition
| baroreceptors in aortic arch and carotid sinus detect changes in blood pressure, increase in blood pressure activates NTS which relay nuclei in medulla and send inhibitory axons to sympathetic preganglionic neurons of intermediolateral cell column of the spinal cord; baroreceptors also activate another population of NTS cells which project to nucleus ambiguus which stimulates parasympathetic innervation of the heart via the vagus nerve reducing heart rate; decrease in BP has opposite effect on this reflex, inhibiting NTS cells and ultimately stimulating sympathetics and inhibiting parasympathetics |
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Term
| chemoreflex to maintain optimal blood gases and pH |
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Definition
| is mixed autonomic and somatic reflex; CV effects-chemorecptors in heart and blood vessels detect changes in blood gases and pH; increase in CO2, decrease in O2 or decreased pH activates cells of the NTS and relay nuclei in the medulla and send excitatory axons to the sympathetic ganglionic neurons; resulting in vasoconstriction of blood vessels, blood pressure and increased heart rate; respiratory efffects-normal respiratory rhythm is driven by a central pattern generator in the medulla and pons but this rhythm can be modulated; chemoreceptors activate NTS, an via relay nuclei in the medulla stimulate motor neurons in the cervical and thoracic spinal cord which cause contraction of the diaphragm and intercostal muscles increasing rate and depth of respiration |
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Term
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Definition
| regulate the glucose supply to maintain energy balance; short term regulation-insulin, gastric distension, CCK |
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Term
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Definition
| parasympathetics stimulate pancreas to release insulin in anticipation of food intake; decreases blood glucose detected by NPY containing neurons in arcuate nucleus of hypothalamus and these neurons project to lateral hypothalamus where they stimulate feeding; rise in blood glucose and insulin is a sateity stimulus resulting in termination of the meal |
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Term
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Definition
| as meal is eaten, mechanoreceptors on visceral sensory neurons are activated in response to distension in GI tract and sensory neurons send signals to NTS in the medulla and signals hypothalamus and cortex resulting in the perception of satiety and cessation of feeding |
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Term
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Definition
| peptide released from duodenum and upper intestine when amino acids and fatty acids are in GI tract; singals visceral sensory neurons which project via vagus nerve to the NTS and then on hypothalamus to decrease feeding |
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Term
| long term regulation of feeding |
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Definition
| brain monitors body fat and maintains homeostatic levels of this energy store in the face of perturbation; leptin-hormonal signal between body fat and the brain and is a circulating hormone release by fat storage cells acts in arcuate nucleus to suppress appetite and stimulate metabolic rate; inhibits NPY contatining neurons in arcuate nuclues; arcuate nucleus neurons also regulate PVN outputs to brainstem and autonomic centeers to stimulate metabolic rate |
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Term
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Definition
| decreased blood pressure signal hypothalamus via vagus and NTS to release vasopressin and acts on kidneys to increase water retention and inhibit urine production; the drop in blood pressure also activates the SNS which constricts blood vessels to counteract the drop in blood pressure |
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Term
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Definition
| vascular organ of the lamina terminalis (OVLT); these stimulates magnocellular cells to release vasopressin and stimulates lateral hypothalamus to produce osmomtric thirst |
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Term
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Definition
| anterior cells detect changes in blood temperatue-signal medial preoptic area to produce hormonal and visceromotor responses and signal lateral hypothalamus to produce somatic motor responses; decreased temperature-hormonal response cold sensitive anterior hypothalamus neurons stimulate TSH release from the anterior pitiuatary and increases cellular metabolism causing visceromotor response-constriction of blood vessels in skin, piloerection and somatic motor response-shivering, warmth seeking behaviors; increased temperature; hormonal response warm sensitive anterior hypothalamus neurons inhbit TSH release and decrease in cellular metabolism; visceromotor response-blood shunted to body periphery to dissipate heat, sweating; somatic motor response-panting, cold seeking behaviors |
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Term
| physiology and behavior of sleep/wake cycle |
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Definition
| cortical activity is measured by EEG, eye movements by EOG, and muscle tone by electromyogram EMG; NREM stage 1:slowing EEG with theta rhythms and have medium EMG; NREM stage 2-slower EEG, spindles, K complexes; NREM stage 3-delta waves with high amplitude slow waves and NREM stage 4 has delta rhythms greater than 50% of the time; REM-fast EEG, low voltage, beta rhythms and rapid eyemovement and no EMG phase in which dreaming occurs |
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Term
| patterns across sleep cycle |
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Definition
| in adult NREM predominates cycling between light and deep sleep and REM episodes increase in frequency and duration later in the night; changes across the life cycle-at birth sleep is fragmented and by adulthood it is consolidated; infants spend equal time awake/REM/NREM by adulthood REM is only 25% of sleep; older adults show more fragmentation of sleep/wake cycle, more naps in day and more awakenings at night |
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Term
| neurons of arousal network |
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Definition
| neuronal activity and NT release is highest during the wake cycle and lowest in sleep cycle;treatments that enhance signaling, promote physiological and behavioral indicatiors or wakefulness; locations reside in brainstem reticular formation and posterior hypothalamus and have broad ascending projections throughout the forebrain |
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Term
| NT and neuropeptide systems of wakefulness |
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Definition
| 1. ACh neurons-pontine reticular formation and basal forebrain; 2. aminergic-norepinephrine in pontine reticular formation, serotonin in midbrain reticular formation, histamine in posterior hypothalamus, dopamine in midbrain reticular formation; 3. hypocretin/orexin-posterior hypothalamus project to other areas of the arousal network in the brainstem reticular formation and posterior hypothalamus |
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Term
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Definition
| GABA location in the anterior hypothalamus and project to arousal network in brainstem reticular formation and posterior hypothalamus |
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Term
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Definition
| ACh neurons reside in the pontine reticular formation and project to thalamus and medial medulla; thalamus projecting REM-on neuorns drive thalamocortical desynchrony in REM and medial medulla projecting REM-on neurons contribute to atonia in REM; normally under inhibitory control by aminergic neurons and when these neurons are silenced in REM sleep the REM-on neurons are disinhibited and show the greates activit and NT release during REM sleep |
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Term
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Definition
| designed to recover to optimal set point when perturbed; implying optimal level of sleep and physiological need for that level |
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Term
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Definition
| endogenous sleep substances-must induce sleep and levels must vary with sleep/wake cycle; adenosine-injections in basal forebrain or anterior hypothalamus induces sleep, breakdown of ATP during prolonged wakefulness by energy systems being run down and this disinhibits anterior hypothalamus neurons by reducing GABA inputs and enhances activity of VLPO sleep promoting cells which inhibit brain regions involved in arousal |
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Term
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Definition
| sleep deprivation-in experimental elevation of sleep pressure induces an increase of slow wave sleep in recovery night in proportion to the sleep loss; naps-reduction of sleep pressure, late day naps produces reduction of SWS in night whereas early day naps do not and naps early day contain less SWS |
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Term
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Definition
| 1.rhythms-behavioral, physiology, hormonal (melatonin) and period in humans is about 25 hrs; 2. entrainment-process whereby the circadian pacemaker is synchronized with 24 hr day where external time cues synchronize the pacemaker |
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Term
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Definition
| of anterior hypothalamus contains the circadian pacemaker; lesions abolish circadian rhythms can be restored by transplantation of SCN from another animal; cells show circadian variation of cellular metabolism, vasopressin release and of neuronal activity in vivo even when the SCN is surgically isolated; GABA is major neurotransmitter of SCN cells and also release VIP and vasopressin |
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Term
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Definition
| 1. retina-population of retinal ganglion cells project directly to it via the RHT which is part of the optic tract until optic chiasm and release glutamate in the SCN which stimulate SCN neurons and this is where entrainment occurs; 2. pineal gland-rhythmically secretes melatonin under the control of SCN, can produce phase shifts; 3. other inputs-5-HT from midbrain raphe, ACh from basal forebrain and midbrain, histamine from posterior hypothalamus; SCN projections to other SCN cells or other parts of the hypothalamus and trigger behavioral physiological and hormonal rhythms |
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Term
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Definition
| 1. desynchronization-when internal clock goes away from external cues/external demands-shift work and jet lag and have stomach ailments, sleep disturbance, fatigue, compromised performance, cognitive and motor; phase shifting-phase advance can be produced by exetrnal time cues introduced late in subjective night and phase delay can be produced by external time cues introduced early in subjective night; melatonin normally secreted at night and if administered in late subjective night have phase delay and if administered in subjective morning have phase advance |
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Term
| drugs that alter the sleep/wake cycle |
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Definition
| 1. serotonin selective reuptake inhibitors-increase 5-HT and decrease REM; 2. tricyclic antidepressants-increase 5-HT and NE and decrease REM; 3. amphetamine like stimulants and increase NE and dopamine and increase waking; 4. benxodiazepines-increase GABA signaling increase sleep; antihistamine-block histamine receptors increase sleep; antipsychotics block dopamine receptors and increase sleep |
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Term
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Definition
| inability to obtain sleep sufficeient length/quality to feel rester the next day tends to increase with age and may be in hyperstate of arousal |
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Term
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Definition
| 1. parasomnias=undesirable behavioral/experiemental phenomena that occurs during sleep dissociated sleep states-sleep walking occurs in stage 4 NREM; sleep terrors-disorder of arousal occurs in stage 4 NREM and initiated by sceam and severe panic followed by prominent motor activity; REM sleep behavior disorder-failure of atonia in REM sleep acting out their dreams and often associated with neurological disorders; |
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Term
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Definition
| sleep attacks during day, excessive daytime sleepiness and sometimes cataplexy, REM abnormalities, hallucinations at sleep onset or offset; sleep paralysis, hypocretin cell loss, low levels of hypocretin in CSF; treatments include naps, regular sleep schedule, stimulants like Ritalin, or modafinil |
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Term
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Definition
| interrupted breathing during sleep, associated with fat build up or loss of muscle tone with aging and upper aiway collapses when muscles relax during sleep and associated with loud snoring, breathing stop and oxygen levels fall and triggers an awakening and restoration of airway muscle tone |
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Term
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Definition
| unpleasant tingling sensations in legs and feet and urge to move them for relief common in older people; constant leg movement in day and gragmented sleep/insomnia at night treated with antiparkinsonian agents, benzodiazepines, opiates, and anti-convulsants |
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Term
| associations with other psychiatric disorders |
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Definition
| 90% patients with major depression have sleep disturbances and also have disrupted circadian rhythms since depression is associated with 5-HT dysfunction, disruption of serotonin input to SCN; seasonal affective disorder, anxiety disorders, adn schizophrenics |
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Term
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Definition
| emotion-state elicited by rewards or punishments; motivation-state in which reward is sought or punisher avoided; feelings-conscious awareness of emotional state; mood-predominant emotional state over time; reward-something for which an animal will work for; punisher-something an animal will work to avoid; emotions are produce by delivery of reward/punisher, omission of reward/punisher; termination of reward/punisher; functions to elicitation of automatic response, flexibility of behavioral response to reinforcing stimuli, motivation, communication, social bonding, survival |
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Term
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Definition
| bilateral temporal lobectomy results in bhevioral syndrome which includes loss of emotional activity (due to loss of amygdala) |
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Term
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Definition
| includes Papez circuit areas: thalamus, hypothalamus, hippocampus, cingulate cortex; and adds amygdala and prefrontal cortex; functions to integrate info from outside world with information about internal body state to generate emotional experience and receives top down control from neocortex for cognitive regulation of emotion |
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Term
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Definition
| sensory info reaches via thalamus (rudimentary, less processed sensory info driving rapid, primitive emotional responses such as fear/startle) and sensory association cortex (more processed sensory information drives subtle emotional states such as anxiety; nuclei include basolateral nucleus and central nucleus |
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Term
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Definition
| 1. hypothalamus-lateral hypothalamus for automatic response and paraventricular nucleus for endocrine response; 2. brainstem PAG-pain modulation and defensive behaviors; 3. brainstem monoaminergic nuclei-altered vigilance and altered sensory perception; 4. prefrontal and cingulate cortex-emotional valence for decision making |
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Term
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Definition
| amygdala lesions in animals produce reduced fear; in animals stimulation causes increased vigilance attention and increased fear and violent aggression and fMRI show activation to presentation of fearful facial expressions |
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Term
| learned fear and emotional memory |
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Definition
| fear conditioning-pairing a neutral stimulas with a painful stimulus leads to autonomic and behavioral responses to the neutral CS that are similar to those elicited by painful stimuli; emotional memory-rapid automatic behavioral responses to emotionally harged stimuli that operate without conscious awareness; thalamocortical inputs to amygdala provide sensory info about both CS and US and outputs include hypothalamus and PAG; declarative memoery of emotional sitiations provides emotional significance to sensory stimuli before they are sent to hippocampus where they reach conscious awareness and formed into memories and these memory traces are much stronger and longer lasting |
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Term
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Definition
| predatory vs affective aggression; amygdala lesions in monkeys alters dominance hierachy |
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Term
| hypothalamus in aggression |
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Definition
| lesions of hypothalamus produces sham rage; medial hypothalamus projects to midbrain PAG and role in affective aggression and lateral hypothalamus projects to the midbrain role in predatory aggression; electrical self stimulation will work to press a lever to deliver electric current into specific brain regions such as the hypothalamus and medial forebrain bundle |
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Term
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Definition
| inputs from the hypothalamus, sensory cortex, reciprocal connections to amygdala and nucleus accumbens; monitors the reward value of different stimuli and detects changes in reward value of learned stimuli and guides behavior based on anticipated reward value of different actions in the contex of long term goals and recognition of emotional signals |
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Term
| lesions of orbitofrontal cortex |
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Definition
| impaired emotional reactivity to stimuli resulting in poor decisions; impaired identification of emotional faces/voices; orbitofrontal syndrome-behavioral disinhibition, emotional lability, inappropriate responses to social cues, lack of interpersonal sensitivity; late maturation of OFC implications for impulsive behaviors during adolescence |
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Term
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Definition
| amygdala encodes the motivational significane of cue, faciliting basic approach avoidance behviors and underlies conditioning and OFC integrates information from the amygdala the nucleus accumbens and other cortical regions to determine value and evalulates changing contigencies to slect and execture appropriate behavioral strategies in the context of long-term goals |
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Term
| olfaction and the limbic system |
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Definition
| olfactory stimuli with emotional impact activate limbic circuitry; olfaction neurons extend cilia into the olfactory mucosa which express receptors to which odorants can bind and the odorants inititate an AP; circuitry-primary olfactory neuron axons from the olfactory nerve which terminates in the olfactory bulb, axons of secondary olfactory neurons in the olfactory bulb from the olfactory tract which projects to the primary olfactory cortex on the uncus of the medial temporal lobe; additional direct and indirect olfactory projections to amygdala, hypothalamus, frontal cortex and hipposcampus underlie the autonomic morot and behavioral responses to olfactory stimuli |
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Term
| anterior cingulate cortex |
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Definition
| integrates visceral, attentional and emotional information with reciprocal connections with the OFC; represents conscious emotional experience-forms a central representation of autonomic arousal; detects conflict between functional state of the organism and new information with potential affective/motivational consequences; assesses the effort required to obtain a reward or avoid a punisher, then sends this information to the OFC for selectionof appropriate behavioral response |
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Term
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Definition
| dysfunction of anterior cingulate and orbitofrontal cortex; OFC/ACC activation during intoxification, craving, drug binging; OFC/ACC activation during drug withdrawl; disruption of self control; increased salience of the value of a drug, increased association of the drug with internal and external cues decrease inhibitory control and increased drive results in compulsive drug taking without regard for adverse consequences |
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Term
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Definition
| 1. auditory-superior temporal gyrus; 2. somesthetic association areas-posterior parietal areas and somatosensory area II; 3. visual association areas-broad territories in occipital lobe |
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Term
| heteromodal association cortex |
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Definition
| multiple sensory systems have input into these cortical areas and integrate information from multiple sensory modalities; associate all the relevenat information regarding perceived objects, regardless of the modality involved in perception; several broad cortical areas including middle temporal gyrus, pareital temporal junction, and posterior part of the parietal lobe, and prefrontal lobe |
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Term
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Definition
| stored information about objects in the world and their interrelationships; ability to indentify and comprehend objects reflects the ability to access information about words, objects, people, places and this is stored in cerebral cortex specifically in widely distribute manner across unimodal and heteromodal and storage of information is dependent on the hippocampal formation and other structures in the medial portion of the temporal lobe |
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Term
| object indentification is important |
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Definition
| assigning meaningful interpretations to words and sentences, to comprehend and generate language, recognizing a face as a face and recognizing specific faces as specific individuals; aquiring new info from perceptual experience and reasoning |
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Term
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Definition
| refers to those neural processes that result in its detection and the awareness of its detection; minimal brain structures required include sensory pathways from receptor up to and including primary sensory cortex; perception provides awareness of the physical attributes of the detected stimulus it is necessary to recognize and comprehend but does not provide recognition and comprehension |
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Term
| specific processes involved in object recognition |
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Definition
| every sensory system receptors abstract and encode many features of the stimuli they detect; processing within primary sensory cortex provides an awareness of the attricbutes of the perceived objects, initially these attributes are not linked together and is fragmented |
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Term
| identification of perceived objects |
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Definition
| requires associating the neural representation of the object with stored info about the object obtained as result of past experience; begins in unimodal association cortex and completes in heteromodal cortex |
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Term
| neural processing in unimodal sensory association areas |
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Definition
| generate a complete neural representation of the perceived object, pattern of activity in population of neurons that represents the attributes of the perceived objects linked together so that they represent the object as a whole and links the fragmented information at primary cortex and is sufficient to determine whether two objects, such as words or face are identical to each other; also begin the process of comprehension by associating the neuronal representation of the perceived object with some of the stored information relevent to the object |
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Term
| neural processing in heteromodal association cortex |
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Definition
| supports cross modal integration that binds together modality specific fragments of information into a coherent whole that integrates the current experience with all relevant knowledge stored in memory |
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Term
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Definition
| damage to the systems described can lead to deficits in object recognition inability to recognize familar objects in the absence of a primary problem detecting a sensory stimulus |
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Term
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Definition
| result from lesions that interfere with the basic perception of sensory inputs, lesions to the unimodal association areas that prevent full integration or elaboration of the raw, fragmented info that arrives in primary cortex |
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Term
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Definition
| result from lesion that prevent linking of stored info with the neural representation of perceived objects the lesions cause these conditions involve more distal unimodal association areas normally have normal perception can describe physical attributes of objects and determine whether two objects are the same or different but show no knowledge of the objects |
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Term
| associative agnosias in visual system |
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Definition
| near the junction of temporal and occipital lobes large lesions can produce global associative visual agnosia and individuals cannot identify anything visually perceived; and smaller lesions can produce focal associative lesions involving particular types or qualities of objects (categorical vs subordinate identifications) and prosopagnosia inability to visually recognize familiar faces caused by bilateral lesions in the inferior temporal lobe near the junction of temporal and occipital but does not prevent the generation of multimodal associations which general or categorical recognition depends so can recognize a face as a face |
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Term
| damage to heteromodal areas |
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Definition
| produce more global deficits in which access of stored info is impaired across modalities lesions in temporal and parietal junction |
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Term
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Definition
| refers to the meanings of words and combined insentences using the rules of grammar and syntax to depict events, thoughts, feelings, etc |
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Term
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Definition
| in most individuals comprehension and expressive aspects of language are mediated principally by the left cerebral hemisphere |
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Term
| Wernickes area and Brocas area |
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Definition
| posterior portion of superior temporal gyrus involved in expression of language; posterior part of inferior frontal gyrus involved in comprehension of language and arcuate fasculus a large axon bundle in the white matter of the cerebral hemisphere that interconnects Wernickes and Brocas areas |
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Term
| Wernickes area and areas around Wernickes |
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Definition
| in parietal and temporal lobes this includes the parietal and temporal junction along with broad areas within the lateral and inferior temporal lobes these areas work together in comprehension and necessary to understand language and also to understand ones own thoughts |
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Term
| Brocas area and broad areas in frontal lobe |
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Definition
| anterior and superior to Brocas and also areas on the medial aspect of the frontal lobe including supplemental motor area and the anterior cingulate gyrus; work together in expression of language by formulating the motor programs for the appropriate words and connecting into appropriate sequences and area is involved in comprehension critical for the interpretation of more complex aspect of grammar in language |
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Term
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Definition
| components of non-dominant hemisphere which is rhythmical and intonational aspect of language and these features add content to the language beyond semantics and syntax such as emphasis and emotion |
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Term
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Definition
| fleunt or receptive aphasia and is notable for comprehension deficits; produced by dysfunction in the temporal parietal junction in the language dominant hemisphere; spontaneous speech is fleunt and grammatically ok but devoid of meaning ; comprehension is impaired-respond inappropriately to questions and unawareness of their own language disorder; also deficient in naming objects and unable to repeat words, sentences etc because dont understand the command and dont understand what they are supposed to repeat |
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Term
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Definition
| notable for non fleunt speech; language assesed by speech in grammatically incorrect and appear to to work very hard and principally content words; comprehension is impaired but simple structure is preserved but tested with sentences having complex grammatical structures; deficient in naming objects and commonly say the wrong word for the test object and are aware when they make errors and can demonstrate comprehension by miming difficulty in generating motor program; unable to repeat words |
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Term
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Definition
| damage to the interconnections between the temporal-parietal junction areas and Brocas area in the dominant hemisphere; fluency is normal and grammatically correct and content is generally OK, comprehension is generally normal and expression of language is generally normal but defect is in repetition performed poorly and characterized by paraphasic errors |
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Term
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Definition
| combination of WErnickes and Brocas aphasisa occurs with compromise of entire middle cerebral artery territory |
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Term
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Definition
| many forms of these and the language deficits are much more subtle than Wernickes and Brocas result from damage to language areas around the two areas so they have good repetition; lesions in language relevant areas in the non-dominant hemisphere can produce deficits in the comprehension and or expression of prosody depending on the location |
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Term
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Definition
| poorly articulated speech due to weakness or paralysis of one or more muscles involved in speech production can be caused by UMN and LMN lesions but language is ok |
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Term
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Definition
| 1. factual info about people, places, things; 2. programs that run automatically and unconsciously for motor skills and habits; 3. episodic memory-autobiographical info about specific episodes; 4. rapid autonomic behavioral responses to emotionaly charged stimuli withou conscious awareness (emotional memory) |
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Term
| different kinds of memory |
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Definition
| 1. working memory-time frame is seconds; 2. short term memory-time period of a few minutes distinct from long term memory; 3. long-term memory-time frame is variable from minutes to a life time |
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Term
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Definition
| process whereby encoded memories, intially labile and easily forgotten become permanent and new memories become integrated with older memories; |
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Term
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Definition
| 1. anterograde amnesia-memory loss that extends foward from a point in time; 2. retrograde amnesia-memory loss that extends backward from a point in time |
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Term
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Definition
| 1. declariative memory- capacity to consciously recollect everyday facts and events and subject to verbal reflection or other means of explicit expresion and very flexible used in comprehension, problem solving, and guiding behavior; 2. procedural memory-skilled performance and non-conscious acquisition of a bias or adaption that is revealed by indirect measures such as performance, is not flexible; 3. emotional memory-implicit and non-conscious and result in conditioned responses to rewards and punishers |
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Term
| categories of declarative memory |
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Definition
| 1. episodic memory-contains representattions of specific personal experiences that occur in a unique spatial and temporal context; 2. semantic memory-body of factual knowledge about the world but not bound to specific experiences/episodes in which the knowledge was aquired |
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Term
| structures of declarative memory |
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Definition
| 1. cortex of the parahippocampul gyrus; 2. hippocampal formation which is deep in parahippocampal gyrus; 3. medial diencephalon including mammillary bodies, anterior nucleus of the thalamus and mammillothalamic tract; 4. hippocampal formation is connected with medial diencephalon by fornix |
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Term
| lesions to medial temporal lobe or medial diencephalon |
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Definition
| causes profound forgetfullness and deficit in encoding new declarative memories and this impairment is mutlimodal but do not impact immediate or procedural memory and can occur without any notable effects on perceptual abilities and intellectual functions |
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Term
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Definition
| consists of multiple systems incudes basal ganglia and cerebellum; basal ganglia participates in learning and memory of stimulus response associations at an unconscious level; procedural system is not flexible, but specific to given task in which learning occured; cerebellum participates in sensory motor adaptions at an unconscious level |
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Term
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Definition
| key structures involved in working memory include the lateral portion of the prefrontal lobe |
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Term
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Definition
| a degenerative disorder that affects memory, and neurons in the hippocampal formation and parahippocampal gyrus are early targets and declarative memory is compromised and neurons may die in many regions of the cerebral cortex and more global memory deficits occur |
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Term
| cholinergic neurons in basal forebrain |
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Definition
| have been implicated in declarative memory functions project to widespread regions of the cortex including all of medial temporal lobe and inhibitors of acetylcholinesterase can lead to modest symptomatic improvements decline in these neurons involved in cognitive decline |
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Term
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Definition
| important when flexibility is needed and critical for rapid redirection of goals and behaviors and in situations when the mapping between sensory inputs, thought, and actions are complex and changing; neural processing within the PF cortex allows goal setting and plan initiate and sequence goal-directed behaviors; consequences of behavioral choices in terms of specific goals are constantly monitored and adjusted as necessary to best accomplish the goals |
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Term
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Definition
| sensory association cortices, providing info about the external world, motor association areas about ongoing and planned motor activites; limbic areas including the amygdala and ventral striatum info about internal, motivational states and emotional weight |
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Term
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Definition
| motor association areas to initiate motor responses required to carry out behavioral choices; sensory association cortices to enhance processing of task relevant sensory inputs relative to irrelevent and therefore distracting sensory inputs and mediate aspects of selective attention; and prefrontal areas interconnect with each other |
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Term
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Definition
| contribute to decision making by dterming the value of expected rewards associated with behavioral choice options; evaluation of integration of ensory and emotional information for reward/punishment value; adapting behavioral choices to changes in the valuation of anticipated outcomes and suppressing responses that are no longer rewarding-motivational and effective aspects of decision making by helping to predict the value |
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Term
| limbic and orbitofrontal areas |
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Definition
| highly cooperative in decision making processes; limbic system is intrumental in assessing stimuli in terms of immediate reward or punishment and stimuli are assessed as rewards or punishers in terms of immediate consequences; orbitofrontal processing of this allows for effective and adaptive decision making by determing the expected value of rewards and punishers in broader context of longer-term goals and allows individuals to forego an immediate reward or accept and immediate punishment for what is judged to be greater long term benefit |
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Term
| bilateral lesions of orbitofrontal portions of prefrontal lobes |
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Definition
| produce deficits in decision making due to insensitivty to future consequences and behavior is guided by immediate prospects and are unable to learn when reward-punishments contingencies change; often aware that their behavior is inappropriate |
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Term
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Definition
| cost or effort required to obtain the reward or outcome; action-reinforcement representation that provides information regarding the likelihood of acheiving reward, the effort required to attain the reward and consequences of expnding the effort vs putting the energy elsewhere; engage in exploratory actions to obtain more info regarding the potential behavioral choices and the probabiity that pursuing a specific action will lead to reinforcement |
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Term
| lateral prefrontal cortex |
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Definition
| involved in many functions relevant to behavior which are generally referred to executive functions include goal formation, planning, carrying out goal directed plans and effective performance with the comparson of expectation and outcomes and flexibly adjusting behavior to bring outcomes in line with expectation (set shifting) and enable us to create a plan to achieve a specific end, initiate the plan, modify the plan based on evaluation of predicted and actual outcomes and persist on the tasks at hand until its completion-working memory |
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Term
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Definition
| large bilateral lesions of orbitofrontal cortex, tend to engage in behaviors that are detrimental to themselves and socially inappropriate |
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Term
|
Definition
| lateral sector plus areas dorsal to the anterior cingulate gyrus, exhibit apathy with loss or diminished initiative and loss or diminished sponaneous thought, movement, and emotional responses and respond abnormally slowly to external stimuli, speech is soft and sloww and comprised of few words, motor impersistance |
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Term
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Definition
| important to achieve and maintain a brain state of high sensitivity to incoming stimuli; active during wakefulness and promotes a brain state in which the thalamus and cortex are responsive to inputs from the external world |
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Term
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Definition
| ability to select specific information from the many sensory input and/or thoughts that are active at any moment in time; can be reflexive and mediated by subcortical structures; can also be deliberate to choose to focus on specific stimuli to accomplish a specific goal or change from one stimulus to another and orchestrated include temporal parietal junction areas, superior pareital areas and the frontal eye fields |
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Term
| parietal and parietal-temporal junctions |
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Definition
| integrate info from all sensory systems to generate a representation of external world and our relationship to the external world; territories in right cerebral hemisphere are concerned with orienting to personal and extrapersonal space bilaterally whereas on the left are only concerned with orienting to space on the right side |
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Term
| lesions in the non-dominant hemisphere |
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Definition
| produce an attentional deficit described as the neglect syndrome and include failure to attend to the left side of the body and of the left side of extrapersonal space not due to lack of perception often have emotional responses even though they are not consiously aware of it; under representation or mis representation of the left side of objects when ask to draw them; deficits in comprehension of the emotional content of language |
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Term
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Definition
| involved in promoting brain processing in situations characterized by conflict and uncertainty, when probability of making an error is high because understanding of the currently operating rules is incomplete-include anterior cingulate cortex, cortex of lateral sector of prefrontal lobe, and basal ganglia components associated with these prefrontal areas; contributes to working memory, multistep planning, behavioral flexibility, and other functions commonly ascribed to prefrontal lobes; tests include Stroop test and Wisconsin card sorting test |
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Term
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Definition
| goal direct behaviors that allow the organism to adapt to internal or external stimuli |
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Term
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Definition
| some motivated behaviors correct an internal change from some optimal set point-reduction of needs or drives; other motivated behaviors are driven by external stimuli but no homeostatic function; incentive motivation-driven by external stimuli that have appetitive or rewarding properties, these external stimuli may override homeostatic drives |
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Term
| neuroanatomy of dopamine system |
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Definition
| 1. nigrostriatal pathway-cell bodies in midbrain reticular formation project to caudate putamen have role in motor function; 2. mesocorticolimbic pathway-in midbrain reticular formation project to cortical and subcortical components of the limbic system specifically the nucleus accumbens with role in motivation; ICSS will cause animals work for stimulation of the fiber tract that containt dopaminergic projections to the limbic structures; DA antatgonists and DA lesions reduce responding for different rewarding stimuli |
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Term
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Definition
| 1. tolerance; 2. withdrawal; 3. craving; 4. continued use despite efforts to stop |
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Term
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Definition
| activate DA NTransmission-produce their immediate effects through different systems (opiods stimulate opoid receptors; cocaine enhances monamine signaling and benzodiazepines enhance GABA signaling); all these drugs elevate DA in limbic structuresof the basal forebrain esp the nucleus accumbens; natural reinforcers and negative reinforcers share this pathway |
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Term
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Definition
| reduced DA function and addiction; devaluation of natural reinforcers, addicts seek drugs becasuse they produce biffer DA effects than natural reinforcers; drug effects are diminished also; causing the addict to seek more and more of the drug |
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Term
| environmental factors for feeding regulation |
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Definition
| combination of homeostatic and non-homeostatic factors; environmental factors include stress, environmental cues, taste, social factors and can override homeostatic mechanisms |
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Term
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Definition
| both neural signals from the periphery (gastric distension) and blood-borne factors (insulin/glucose, CCK) whose release is triggered by food signal the lateral hypothalamus to regulate feeding and control meal size and frequency |
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Term
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Definition
| leptin is released from fat cells, inhibiting NPY release in hypothalamus resulting in suppression of feeding and stimulation metabolism for the purpose of body weight maintainence |
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Term
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Definition
| inhibits feeding; diffent receptors regulate different aspects of feeding (meal size, rate of eating, continuity of feeding); site of HT effects is in hypothalamus and reduces size and duration of meals but not onset latency or meal frequency and influences termination and not initiation of feeding; hypothalamic 5HT responds to carbohydrate ingestion and high carb diets increase hypothalamic 5HT and stimulating agents reduce craving for carb |
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Term
| 5HT interactions with leptin and CCK |
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Definition
| all parallel behavior and neurochemical effects and receptors are located in same nuclei of the hypothalamus; CCK may be coreleased with 5HT from the same neurons, prolonging the actions of 5HT on feeding; satiety is produced by combinatorial actions of 5HT, leptin, and CCK |
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Term
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Definition
| pathology-decreased 5HT levels in brain and this is associated with increased carb preference; pharm treatment-fenphen causes an increase in 5HT release, suppresses appetite but taken off the market when associated with heart valve defect; SSRIs and 5HT/NE uptake blockers |
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Term
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Definition
| bulimia-disorder in prodction of satiety that leads to binging and overcomsumption of carbohydrates and or fat; deficeinet 5HT brain activity and reduced postsynaptic 5HT response; reduced 5HT is associated with increase binge frequency |
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Term
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Definition
| requires 1. selectivity-ability to make selective responses to specific stimuli; 2. filtering-ability to screen extraneous inputs; 3. felxibility-ability to adjust to new events and conditions |
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Term
| locus coeruleus-norepinephrine system |
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Definition
| located in pontine reticular formation has excitatory and inhibitory medulla inputs and from limbic structures including amygdala and medial prefrontal cortex; projects to sensory regions of brain stem and spinal cord and cortex, hippocampus, thalamus, hypothtalmus, and cerebellum and cortical areas associated with attentional processing |
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Term
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Definition
| 1. tonic activity-spontaneous firing rate, may contribute to behavioral flexibility or scanning attentiveness; 2. phasic activity-episodic bursts of firing activity may contribute to selective attention-stimulus evoked response |
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Term
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Definition
| visual discrimination task-monkeys are trained to focus on a central fixation point, press a level during presentation of a stimulus at the fixation point and release the lever when different stimulus appears; record tonic and phasic LC activity and good task performnace spontaneous tonic LC activity in intermediate range; high error rate-spontaneous LC activity in elevated range |
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