Term
|
Definition
| Ascending Reticular Activating System - found in the rostral Reticular formation. Projects to the cortex, thalamus and limbic system, maintains the brain in a state of arousal. |
|
|
Term
| Lesions in the ARAS can lead to? |
|
Definition
| Unconsciousness and coma. |
|
|
Term
| Rostral Brain Stem Reticular Formation Fxn? |
|
Definition
| Behavioral and arousal. Very important in sleep and consciousness. Neurons here respond to all sensory stimuli and sharpen attentive state. Consists of Midbrain and upper Pons. |
|
|
Term
| Differentiate ARAS from Lemniscal system. |
|
Definition
| ARAS consists of multiple parallel and interacting systems, essential for maintaining consciousness. Conveys non-specific information related to arousal. Lemniscal system projects specific sensory information to the thalamus and cerebral cortex. |
|
|
Term
| ARAS works in parallel with? |
|
Definition
| The lemniscal system. Whenever a sense is activated, ARAS system arouses the brain to receive it. |
|
|
Term
| Projections from the ARAS are directed to? |
|
Definition
| Intralaminar nuclei of thalamus and midline thalamic nuclei which direct signal throughout basal ganglia and cerebral cortex. |
|
|
Term
| Pain modulation derives from? |
|
Definition
| Caudal brain stem reticular formation. Specifically - Raphe nuclei and cells in the periaqueductal gray send projections down to spinal cord in SUBSTANTIAL GELATINOSA. |
|
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Term
| Activation of Raphe Nuclei and cells in the periaqueductal gray lead to? |
|
Definition
| Reduced pain perception. Therapeutic stimulators implanted have been successful in patients with intractable pain. Area also has opiate receptors, suggesting a role for pain modulation by endogenous opiates (endorphins). |
|
|
Term
|
Definition
| Chronis cleep disorder, affecting approx 250K people in U.S. Characterizes as a REM sleep attack during daytime lasting from 30 secs to 30 mins, without passing through SWS cycle. |
|
|
Term
| Abrupt onset narcolepsy is termed? |
|
Definition
|
|
Term
| Narcolepsy thought to be caused by? |
|
Definition
| A genetic disorder - possibly triggered by an autoimmune response. Mutation in Orx-2 receptor gene. |
|
|
Term
|
Definition
| Diffuse core of highly branched neurons that extend the entire length of the brain stem and into the spinal cord. |
|
|
Term
| 2 divisions of the Reticular formation. |
|
Definition
Rostral - midbrain and upper pons - fxns to maintain an alert, conscious state in forebrain. (AKA mesencephalic and rostral pontine reticular formation).
Caudal - clore of lower pons and medulla and spinal cord. Fxn descending motor control (reticulospinal path) brainstem reflexes, autonomic functions. |
|
|
Term
| Projections into the spinal cord from the reticular formation represent? |
|
Definition
| RETICULOSPINAL TRACT - that ends on interneurons controlling trunk and axial muscles. |
|
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Term
| In the lower pons and medulla, Reticular Formation neurons control? |
|
Definition
1) Visceral and somatic motor nuclei.
2) ANS coordination
3) Descending motor control. |
|
|
Term
| Caudal brainstem reticular formation ANS coordinate? |
|
Definition
| GI responses, respiratory, cardiovascular, orofacial descending motor control, med and lateral reticulospinal motor tracts. These descend to interneurons which in turn project to motor neurons controlling trunk and equilibrium (proximal muscles) for balance. |
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|
Term
| Oculomotor system responsible for 5 types of eye movments. |
|
Definition
1) Saccades - ballistic, not feedback regulated, movement is preprogrammed - moved fovea from 1 target to another. REsets gaze as limit of eye motion is reached.
2) Smooth pursuit - foveate a moving target. Cerebellum and vestibular nuclei are involved. Driven by retinal slip reflexive for optokinetic reflex.
3) Vergence - adjusts angle of each eye to keep image in fovea of both eyes (near reflex)
4) Vestibulo-ocular reflex - keeps objects foveated with movement of head.
5) Optokinetic reflex - foveate moving object while head remains stationary. |
|
|
Term
| Nystagmus is named relative to what motion? |
|
Definition
| The direction of the fast saccade. A slow movement to the right followed by a fast saccade back to the left would be a "left" nystagmus. |
|
|
Term
| Caloric Test for vestibular function. |
|
Definition
| COWS - cold water and warm water applied at different times. With Cold water - nystagmus is opposite to ear where water is applied. With warm water - nystagmus to the same side. |
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|
Term
| Unilateral damage to the vestibular system could cause what with regard to eye movement? |
|
Definition
| Pathological nystagmus. Silencing of the spontaneous output from the damaged side results in an unphysiological difference in firing rate because the spontaneous discharge from the intact side remains. |
|
|
Term
| COWS test in patients who are comatose due to dysfunction of both cerebral hemispheres while brainstem remains in tact? |
|
Definition
| Saccadic movements are no longer made and the response to cold water consists of only the slow movement component of the eyes to side of the irrigated ear. |
|
|
Term
| For effective binocular vision, an object needs to be? |
|
Definition
|
|
Term
| Two methods for "foveating" an object. |
|
Definition
1) move eyes w/i orbits - oculomotor system.
2) move orbits in space - head movement. |
|
|
Term
| Four primary subnuclei in Vestibular Complex? |
|
Definition
| 1&2) Superior and Medial - coordinate head and eye movement via VOR. Input from semicircular canals, output: contralateral projection via MLF to motor nuclei III, IV, VI. 3) Lateral nucleus - postural control. Input: otoliths. Output: ipsilat all levels of spinal cord via Lateral Vestibulospinal Tract. 4) Descending nucleus - Head position- projects bilateraly to cervical spine via MLF. |
|
|
Term
| 3 Primary functions of the vestibular system. |
|
Definition
1) Maintain posture
2) Maintain muscle tone
3) Stabilize gaze during movement (VOR). |
|
|
Term
| Cell bodies of vestibular nerve located? Project to? |
|
Definition
| Vestibular ganglion (Scarpa's), project to vestibular complex of brain stem. |
|
|
Term
| Vestibular nuclei are considered important? Receive input from? |
|
Definition
1) Centers of Integration.
2) Vestibular nerve, Vision system, Cerebellum, somatic and proprioceptive inputs. |
|
|
Term
| Sensory organ of the semicircular canal? |
|
Definition
| CRISTA - located in the AMPULLA. |
|
|
Term
| In the semicircular canal, the hair bundles of the CRISTA are anchored in the? |
|
Definition
| CUPULA - movement of head causes movement of endolymph w/i canals, which displaces relatively compliant cupula, causing depolarization on one side and hyperpolarization on the other side (of head). |
|
|
Term
| How is Adaptation established in the semi-circular canals? |
|
Definition
| Endolymph reaches same velocity as head within approx 10-20 seconds. |
|
|
Term
| Vestibular hair cells are located in membrane called? |
|
Definition
|
|
Term
| Hair bundles of the macula (vestibular system) are embedded in? |
|
Definition
| Otolithic membrane (calcium carbonate otoliths). |
|
|
Term
| What divides the Utricle and Saccula into halves? |
|
Definition
| Striola - hair cells are arranged in geometrically opposed orientations - in order to respond to displacement with opposite polarities. Also slight curved, so that motion is ultimately encoded by a complex pattern. |
|
|
Term
| Difference between detection of utricle and saccule |
|
Definition
Utricle - detects linear acceleration.
Saccule - Gravitational acceleration.
Semi-circular canals - angular acceleration. |
|
|
Term
| Components of the vestibular system? |
|
Definition
Bony labrynth in temporal bone.
Otolith organs (utricle and saccula)
Semicircular canals
Filled with endolymph - reaches endolymphatic duct. |
|
|
Term
| Hair cells are depolarized with what movement? |
|
Definition
| Movement towards the Kinocilium. Depolarization when moving away from kinocilium. |
|
|
Term
| Continuous stimulation of hair cells leads to? How? |
|
Definition
| Adaptation. Modulation of tension in "gating spring" by movement of attachment points via a myesin motor. |
|
|
Term
| What is the neurotransmitter used in the synaptic terminals of the vestibular system? |
|
Definition
|
|
Term
| Right cerebral hemisphere performs better at? |
|
Definition
| Pattern formation, spatial and perceptual problems. |
|
|
Term
| Control of behavior is performed best by which cerebral hemisphere? |
|
Definition
| Either hemisphere has about equal control. |
|
|
Term
| The limbic system is associated with what functions? |
|
Definition
| HOME: Homeostasis, Olfaction, Memory, Emotion. |
|
|
Term
| Declarative memory is maintained where? |
|
Definition
| Medial regions of temporal lobe and medial diencephalon (mammillary bodies) |
|
|
Term
| Non-declarative memory is maintained where? |
|
Definition
| Cerebellum and basal ganglia for motor skill and habits, amygdala for emotional memory. |
|
|
Term
| Consolidation of short term memories part of? |
|
Definition
| Medial temporal lobe (hippocampus) but not responsible for repository of childhood memories. |
|
|
Term
| Majority of hippocampal inputs arrive via? |
|
Definition
| Perforant & alvear pathways from nearby entorhinal cortex. |
|
|
Term
| Modulatory serotonergic and noradrenergic inputs to hippocampus arrive from. |
|
Definition
Raphe nucleus - Serotonin
Locus ceruleus - Norepinephrine (noradrenaline) |
|
|
Term
| Describe Papez's circuit. |
|
Definition
| Starts from hippocampus primarly via CA3 region, -> fimbria -> fornix (crus, body, columns) -> mamillary bodies -> mamillothalamic tract -> Anterior nucleus of thalamus -> cingulate gyrus -> cingulum -> entorrhinal cortex -> hippocampus. |
|
|
Term
|
Definition
| Plays an important role in both emotional expression and memory. |
|
|
Term
| Fornix sends branches off at anterior commissure. What are they - where do they go? |
|
Definition
| Just before anterior commissure - to nucleus accumbens and septal nuclei. |
|
|
Term
| What is long term potentiation (LTP)? |
|
Definition
| Has to do with synaptic plasticity. Strength of individual synapses can be dramatically increased by precisely timed incoming signals. CA1 & CA3 potentiation can last for many hours to days (consolidation of memories). |
|
|
Term
|
Definition
| Many mechanisms in both pre and post synaptic terminals. Best known has to do with AMPA and NMDA glutamate receptors on dendritic spines. These are glutamate activated cation channels. NMDA is very permeable to CA2+ but at normal resting potentials, NMDAs are blocked by Mg2+. Glutamate binding to AMPA receptors activates a depolarizing current. Potent and sustained AMPA activation can sufficiently depolarize the membrane as to displace Mg2+ from the NMDA channels, resulting in a rapid influx of Ca2+ = increased cellular mechanism, increased kinases that increase synaptice efficiency which = additional AMPA receptors at membrane. Increased CA2+ also triggers release of retrograde messengers that facilitate neurotransmitter release at pre-synaptic terminal. |
|
|
Term
| Only naturally disconjugated eye movement? |
|
Definition
|
|
Term
| Where is CN3 nucleus located at what level of midbrain? |
|
Definition
| Mesencephalic reticular formation of midbrain, same level as superior colliculus. |
|
|
Term
| Limbic system modulates or regulates the what? |
|
Definition
| Behavioral mechanisms controlled by the hypothalamus. |
|
|
Term
| Many structures in the limbic system have what type of receptors? |
|
Definition
|
|
Term
| RIN with regard to eye movement centers? |
|
Definition
| Rostral Interstitial Nucleus - vertical eye movements. |
|
|
Term
| Gaze center responsible for horizontal gaze? |
|
Definition
| PPRF - Paramedian Pontine Reticular Formation. |
|
|
Term
| Cortical control of eye movement executed via? |
|
Definition
| FEF - frontal eye fields, project to contralateral PPRF, which activates ipsilateral abducens and inhibits activity in contralateral abducens. |
|
|
Term
| RIN projects to which ocular muscles? |
|
Definition
1) Bilaterally to elevators of the eye,
2) Ipsilateral to inferior recti,
3) Contralateral to superior oblique. |
|
|
Term
| Vergence controlled by what area of the brain? |
|
Definition
| Dorsal Midbrain Reticular Formation. Inervates medial rectus nucleus w/i oculomotor nucleus w/o innervating the contralateral abducens nucleus. |
|
|
Term
|
Definition
| Abnormal alignment of eyes - can be due to defects of extraocular muscles or damage to cranial nerves. |
|
|
Term
|
Definition
| Defects in cranial nerves innervating extraocular muscles. |
|
|
Term
|
Definition
| Extorsion and slight elevation of eye. |
|
|
Term
|
Definition
| Affected eye unable to fully abduct (ipsilaterally). |
|
|
Term
| Lateral gaze palsy is what? |
|
Definition
| Damage to abducens nucleus - involves both eyes due to neural yoking through MLF. |
|
|
Term
| What is Internuclear opthalmoplegia (INO)? |
|
Definition
| Defect in conjugate eye movement, in which 1 eye does not fully adduct during attempted horizontal gaze. Caused by lesion in the IPSILATERAL MLF, preventing proper activation of medial rectus. Caused by MS, pontine infarcts, neoplasm of MLF. |
|
|
Term
| What is one-and-a-half syndrome? |
|
Definition
| Caused by combined INO (ipsilaterally) as well as ipsilateral nerve palsy. Ipsilateral eye cannot move horizontally at all, contralateral eye loses half of its mobility - unable to adduct, can only abduct. |
|
|
Term
| With regard to the sleep / awake cycle, when we shift to a condition of wakefulness, what takes place with regard to nuclei and neurotransmitters? |
|
Definition
| Tuberomamillary neurons containing (OREXIN)are activated - neurons inhibit the prioptic nucleus and activate the ARAS as well as brainstem nuclei, also Interlaminary and midline nuclei of the thalamus |
|
|
Term
| Vertical saccades are controlled by? |
|
Definition
| RIN (Rostral Interstitial Nucleus). |
|
|
Term
| Smooth pursuit of objects controlled by what ocular areas? |
|
Definition
| Commands are generated in the extrastriate visual cortex (MT:Motion areas) which calculate direction and velocity. These areas project to frontal eye fields on ipsilateral side. Dorsallateral Pontine Nuclei relays cortical input to cerebellum, which in turn transmits command to oculomotor nuclei. |
|
|
Term
| These nuclei are in the circuit for smooth pursuit of objects (eyes), and receive inputs from FEFs on ipsilateral side, and relay information to cerebellum. |
|
Definition
| Dorsolateral Pontine Nuclei. |
|
|
Term
|
Definition
State in which a patient is
1) Unarousable and unresponsive.
2) Pt's eyes are closed
3) Brainstem reflexes are present, however there are no purposeful responses to stimuli.
4) No sleep/awake cycles. |
|
|
Term
Compare Sleep, vegetative, coma, and brain death categories with regard to
1. Brainstem reflex
2. Sleep / awake cycles
3. Purposefull response to stimuli |
|
Definition
            BS Reflex     sleep/awake cycle  Resp to
                                                         stimuli
sleep           Y                Y                    Y
Â
Vegetative    Y                Y                   N
Â
coma            Y                N                    N
Â
Brain death   N                N                    N |
|
|
Term
| During coma, cerebral metabolism does what? |
|
Definition
|
|
Term
| In brain death, what do you find with regard to brain activity? |
|
Definition
| No ECG activity, No brainstem or forebrain activity, cerebral perfusion and metabolism are zero. |
|
|
Term
|
Definition
| A reversible state of unconsciousness. |
|
|
Term
| Sleep is an active/ inactive process? |
|
Definition
| Active - regulated by sleep specific centers. Not a single state, but a cycle of successive stages. |
|
|
Term
| Two major stages of sleep are? |
|
Definition
1) SWS or slow wave sleep (synchronized sleep) because of the slow apparently synchronized regular EEG pattern.
2) REM or rapid eye movement sleep. This is also know as de-synchronized or paradoxical sleep. |
|
|
Term
| How many substages are there in SWS sleep? |
|
Definition
| 4 stages to slow wave sleep. Each stage from 1 to 4 gets progressively longer. 4th stage is the longest. |
|
|
Term
| The 2 major sleep stages SWS/REM go through a complete cycle about every how many minutes? |
|
Definition
|
|
Term
| What physiological changes occur in slow wave sleep? |
|
Definition
Minimal changes when compared to awake state.
1) Spinal reflexes are present
2) Progressive decrease in heart rate and respiratory rate. |
|
|
Term
| What physiological changes occur in paradoxical or REM sleep? |
|
Definition
1) Profound decrease in muscle tone.
2) EEG resembles awake state - low voltage, high frequency, de-synchronized.
3) Dreaming occurs as well as penile erection |
|
|
Term
| What two nuclei in the hypothalamus are specifically associated with control of sleep and wakefulness? |
|
Definition
1) Prepotic nuclei - when activated - is involved in sleep.
Tuberomammillary nuclei - when activated - is involved in wakefulness - cortical arousal. |
|
|
Term
| With regard to each other, the tuberomammilary and preoptic nuclei are considered to be what? |
|
Definition
|
|
Term
| Nystagmus is normally caused by? |
|
Definition
| Cerebellar disease or lesions. |
|
|
Term
| Damage to the pontine nuclei associated with the ocular system will often lead to? |
|
Definition
| Absence of smooth pursuit - replaced by saccades. |
|
|
Term
| Damage to cerebellar nuclei often results in what type of ocular movement dysfunction? |
|
Definition
|
|
Term
| With regard to cerebral lateralization, what is noted reference the planum temporale? |
|
Definition
| Significantly larger on the left side in the majority of patients. |
|
|
Term
| Lesions to the left vs right side of speech areas will result in what defects? |
|
Definition
| Left dominant speech regions will result in "major aphasias", non-dominant speech areas, not major language deficits, but rather perceptual changes. |
|
|
Term
| Broca's area is defined as what area? What function? |
|
Definition
| Opercular area that is associated with motor speech, controls movements of articulation, facial expression, and phonation. Specifically the triangular and opercular areas of the inferior frontal gyrus. |
|
|
Term
| Wernicke's area location and function? |
|
Definition
| Located at the posterior aspect of the superior temporal gyrus, includes auditory comprehension center. |
|
|
Term
| What tract connects Wernicke's area with Broca's area? |
|
Definition
|
|
Term
| What are 6 stages or steps in naming an object? |
|
Definition
1) Retina transmits image to LGN and then to primary visual cortex.
2) Signal then to higher order visual area.
3) Sensory association cortex in angular gyrus (receives info from all sensory modalities.
4) to wernicke's area, language comprehension, stored memories that represent word as seen or heard.
5) Arcuate fasciculus to Broca's area
6) Broca's area to facial area of motor cortex. |
|
|
Term
| Characteristics of Wernicke's aphasia? |
|
Definition
Deficit in comprehension of language.
1) Damage to left or speech dominant posterior superior temporal lobe.
2) Verbal output and fluent comprehension is impaired. Neither spoken or written word is comprehended.
3) Empty speech - many words used by with little meaning. Word salad. |
|
|
Term
| Characteristics of Broca's Aphasia? |
|
Definition
Damage to motor association cortex (inferior frontal gyrus - opercular and triangular parts).
1) Comprehension preserved but language is not fluent.
2) Right hemiparesis is usually present. |
|
|
Term
| What is conduction aphasia? |
|
Definition
| Lesion in the arcuate fasciculus. Fluent speech and comprehension is good but there is a tendency to use incorrect words or wrong combinations of works (Paraphasia). |
|
|
Term
| If someone can read silently (normally) and has good comprehension, but reading aloud is abnormal, you might suspect? |
|
Definition
| Conduction aphasia - lesion in the arcuate fasciculus. |
|
|
Term
|
Definition
| Pure word blindness. Could result from damage to left occipital cortex AND damage to the splenium of the corpus callosum. Right visual visual field is lost because it projects onto the left visual cortex. |
|
|
Term
|
Definition
| difficult in learning to read. May result from a congenital failure of left hemisphere to dominate. |
|
|
Term
| What are characteristics of dyslexia? |
|
Definition
| In dyslexic males, the planum temporale has a much less degree of difference between the left and right hemispheres. Also, the left LGN shows histological abnormalities. |
|
|
Term
| Aphasias occur most often post what? |
|
Definition
| Stroke or other major vascular disorders in cerebral hemispheres. |
|
|
Term
| Post commissureotomoies, what does a patient typically display? |
|
Definition
| Mute - cannot communicate verbally, but can perform basic cortical functions such as sensory analysis, calculation, memory, learning. |
|
|
Term
| The right hemisphere by itself has deficits in what type of functions? |
|
Definition
| Less capable of complex reasoning and analysis. Capable of "primitive" understanding of language. |
|
|
Term
| What is parietal lobe syndrome? |
|
Definition
Representational neglect. Failure to recognize 1 side of body. Paralysis on 1 side of body. Drawing test - copy part of a drawing, neglecting side contralateral to site of lesion.
Caused: Usually due to stroke in posterior parietal lobe of non-dominant hemisphere (purest form). |
|
|
Term
| What is psychogenic amnesia? |
|
Definition
| Instead of pattern anterograde or retrograde amnesia, pt has loss of memory of specific events that hold specific emotional significance. |
|
|
Term
| Normal memory loss is associated with? |
|
Definition
Infantile amnesia
Benign senescent forgetfulness
Sleep - dreams
Just regular forgetting. |
|
|
Term
| Right sided lesions of the cerebellum will result in deficits to which side? |
|
Definition
|
|
Term
| The limbic system is involved in what areas of function? |
|
Definition
| HOME: Homeostasis, Olfaction, Memory, Emotion. |
|
|
Term
| Main visible components of the limbic system? |
|
Definition
| Cingulate gyrus, parahippocampal gyrus, uncus. |
|
|
Term
| What virus seems to have a tropism for the limbic cortex? |
|
Definition
| Herpes simplex virus - can cause severe encephalitis. |
|
|
Term
| Primary olfactory cortex consists of? |
|
Definition
| Piriform cortex and periamygdaloid cortex. |
|
|
Term
| The olfactory bulb projects to? |
|
Definition
| Projects via mitral and tufted cell axons via lateral stria to the cortex olfactory cortex as well as the amygdala. Primary olfactory cortex projects to the anterior entorrhinal cortex. |
|
|
Term
| What two areas appear to be critical for memory formation, consolidation, and retrieval? |
|
Definition
1) medial temporal lobe (hippocampal formation and adjacent cortex (parahippocampal gyrus)
2) Medial diencephalic areas - mediodorsal thalamic nucleus, anterior thalamic nucleus, intermedullary lamina, mammillary bodies. |
|
|
Term
| Hippocampal formation is truly comprised of three parts which are? |
|
Definition
1) Hippocampus proper
2) Dentate
3) Subiculum |
|
|
Term
| Storage process of memory is believed to occur where? |
|
Definition
| In the association and primary cortices, that allow a specific memory to be reactivated. |
|
|
Term
| Out put from hippocampus projects to? |
|
Definition
1) Subiculum then to entorrhinal cortex, then multimodal association cortex.
2) Fornix (via subiculum) to diencephalon and septal nuclei. |
|
|
Term
| Input to the hippocampus arise from the contralateral hippocampus via? |
|
Definition
| Hippocampal commissure - located between the fornices. |
|
|
Term
| What are functional parts of the fornix? |
|
Definition
1) Output fibers from hippocampal formation forms white matter layer called: alveus
2) then fimbriae, crura, body, columns. |
|
|
Term
| Axons from fornix have 3 targets - they are? |
|
Definition
1) Mamillary bodies
2) Anterior nucleus of the thalamus
3) Lateral septal nuclei - via precommissural fornices. |
|
|
Term
| Some fibers travel back in the fornix to the hippocampus, what are they? |
|
Definition
| Cholinergic neurons from medial septal nuclei to reach the hippocampal formation. Travel along with GABAergic projections (also in fornix), may play important role in memory function. |
|
|
Term
| In Papez's circuit, do all axons traveling in the fornix first pass through the mamillary bodies and then to the anterior thalamic nucleus? |
|
Definition
| NO. Some fibers go directly to anterior thalamic nucleus w/o traveling through mammillary bodies. |
|
|
Term
| Declarative vs. non-declarative memory. |
|
Definition
Declarative - explicit: conscious recollection of facts or expereinces.
non-declarative (implicit): nonconscious learning of skills, habits, other acquired behaviors. |
|
|
Term
|
Definition
| Declarative memory loss, typical of bi-lateral medial temporal lobe or bilat medial diencephalic lesions. If there are only unilateral lesions - typically no significant deficits. However: Unilateral dominant = deficits in verbal memory (usually left side). Unilateral non-dominant = deficits in visual / spatial memory. |
|
|
Term
| What type of lesions result in specific non-declarative memory loss? |
|
Definition
| (this would be learning, skills/habits). Not specifically identified. Most likely involves plasticity in several areas. The CAUDATE appears significant in habit learning, pathology may be linked to OCD. |
|
|
Term
| Deficits in this area of the brain have been potentially linked to OCD. |
|
Definition
|
|
Term
| Bedside memory testing involves investigating what areas? |
|
Definition
- Immediate recall - 1-2 mins
- Attention
- Working memory: holding concept briefly in awareness while performing a mental operation.
- Recent memmory (4-5 mins)
- Remote memory: past history - childhood, etc. |
|
|
Term
| Medial temporal and diencephalon structures appear to do what function with regard to memory? |
|
Definition
| Mediate process by which declarative memory is gradually consolidated in the neocortex. |
|
|
Term
|
Definition
| From time of lesion forward - often seen in bilateral lesions of medial temporal/diencephalon areas. |
|
|
Term
|
Definition
| Prior to time of lesion - also seen in bilateral injury of medial temporal / diencephalon areas, but also with concusions. |
|
|
Term
| With damage to the medial temporal and diencephalon areas, what memories are still retrievable? |
|
Definition
| Older memories - several years prior to lesion can be retrieved without function of this area. |
|
|
Term
| Memory mechanisms involved in time domain of memory consolidation. |
|
Definition
1. First seconds: electrical activity and second messenger systems.
2. Mins to hours: protein phosphorylation, covalent modification, expression of early genes.
3. Hours to years: Change in gene transcription and translation. Structural change of proteins and neurons. |
|
|
Term
| Anatomical structures involved with memory processing over the dynamic of time. |
|
Definition
1. <1 second brainstem, frontoparietal assoc.
2. Secs to min: Frontal association cortex.
3. Mins to years: med temporal and diencephalonic structures.
4. Years: specific corticies. |
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Term
| What deficits to memory might be expected with cerebral contusions from head trauma? |
|
Definition
| Often involve anteromedial temporal lobes as well as basal orbitofrontal cortex, resulting in permanent deficits in memory. |
|
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Term
| Concussions often result in what type of memory impairment? |
|
Definition
| Memory loss that is usually reversible except for a few hours around the time of injury. |
|
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Term
| Infarcts or ischemia usually results in what type of memory deficits? |
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Definition
| Memory deficits especially when bilateral medial temporal or medial diencephalic structures are affected. Arterial lesions at top of basilar artery can cause bilateral damage as described. Med thalamus is perfused by initial segments of the PCA. Medial temporal lobes are perfused by distal branches of the PCA. |
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Term
| Global cerebral anoxia caused by a cardiac arrest may lead to what with regard to memory? |
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Definition
| Prominent memory loss - due to particular vulnerability of hippocampus to anoxic injury. |
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Term
| An anterior communicating artery aneurysm often results in? |
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Definition
| Damage to basal forebrain - memory loss together with other deficits. |
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Term
| What is Wernicke-korsakoff syndrome? |
|
Definition
| Thiamine deficiency - occurs in alcoholics as well as those with chronic parenteral nutrition. Results in bilateral necrosis of mammillary bodies, variety of medial diencephalic and other periventricular nuclei. Pts who survive are left with anterograde and retrograde amnesia as well as other neuropsychological deficits (frontal lobe dysfunction). This usually involves judgment, impusles control, initiation, lack of awareness and memory deficit. |
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Term
| What is the triad of symptoms associated with Wernicke-Korsakoff syndrome? |
|
Definition
The drunken "ACE" flying the plane.
1. Ataxia
2. Confusion
3. Eye movement abnormalities. |
|
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Term
| Transient global amnesia is characterized as? |
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Definition
| Abrupt development of retrograde and anterograde amnesia with no obvious cause and no other deficits. Often occurs in settings of physical exertion or emotional distress. Characteristically ask same question over and over with no recollection of asking question. Typically lasts 4-12 hours. Full recovery with only permanent loss of a few hours before and after onset. About 85% of pt will have no recurrent episodes. |
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Term
| Alzheimers disease characterized as? |
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Definition
| Usually starts with memory loss for recent events without other deficits. ALZ preferentially affects bilateral hippocampal temporal and basal forebrain structures. |
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Term
| Summary role of entorhinal cortex? |
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Definition
| Input/output to hippocampus. Critical position to form and express memories. This is one of the first areas of degeneration in Alzheimers disease. |
|
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Term
| One of first areas of degeneration in Alzheimer's disease is? |
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Definition
|
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Term
| Papez's circuit is characterized as being involved in? |
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Definition
| It is the intersection of memory and emotion. Structures associated with hippocampal formation , hypothalamus, cerebral cortex. Anatomical basis of emotion and memory. |
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Term
| Axons leave subiculum of hippocampal formation and form what? |
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Definition
| Fringe (fimbria), then fornix, then travel to hypothalamus (mamillary body and lateral hypothalamus). |
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Term
| Once activated, mamillary bodies connect with? |
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Definition
| Anterior thalamic nucleus via the mammilothalamic tract. |
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Term
| The prominent tract from the cingulate gyrus to the hippocampal formation is called? |
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Definition
| Singulum. This is a target for "anterior cingulotomy". |
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Term
| "Anterior cingulotomy" is sometimes performed on patients with? |
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Definition
| Retractable pain - which often relieves the emotional component of that pain - this is a neurosurgical procedure. |
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Term
| Absence of social reserve, lack of emotions such as fear and anger, could be attributed to? |
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Definition
| Bilateral lesion of the amygdala. |
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Term
| PET scans indicate that the amygdala is more active when experiencing? |
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Definition
| Fearful facial expressions. |
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Term
| With regard to human interrelations, the amygdala is vital for? |
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Definition
| Expression of fear or aggression and for the recognition of those emotions in others. |
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Term
| First cortex to be affected by Alzheimers is often? |
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Definition
|
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Term
| In Alzheimers, neurons are lost where? |
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Definition
| Hippocampus and parahippocampal regions. |
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Term
| Alzheimers results in loss of neurons as well as reduction in? |
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Definition
| Cholinergic innervation of cerebral cortex. Degeneration of large cholinergic neurons in base of forebrain, especially within septum pellucidum. Normally axons project to neocortex, explaining cognitive loss (deficit). Also project to amygdala, resultin in abnormal behaviors. |
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Term
| Two consistent histological findings with alzheimers patients. |
|
Definition
1. Neurofibrillary tangles -
2. Neuriti plaques.
Frequency of these findings correlate to degree of dementia. No known relationships between 1 and 2. |
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Term
| Amyloid precursor proteins (APP) usually associated with? |
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Definition
| Neuritic plaques in ALZ pts. |
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Term
| Role of the hypothalamus? |
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Definition
| Regulates internal environment "homeostasis". Integrates autonomal, somatic, hormonal, behavioral. Limbic -> hypothalamus -> autonomic, somatic, hormonal, behavioral. |
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Term
| Hypothalamus bordered posteriorly by? Anteriorly? |
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Definition
| Post: Mammilary bodies. Ant: Lamina terminalis |
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Term
| Hypothalamus is divided into three regions. |
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Definition
1. Supraoptic
2. Tuberal
3. mammillary |
|
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Term
| Which nuclei comprise the supraoptic region of the hypothalamus? |
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Definition
Supra optic PASS es above.
1. Supraoptic N.
2. Suprachiasmatic N.
3. Paraventricular N.
4. Anterior hypothalamic N. |
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Term
| Which nuclei comprise the tuberal region of the hypothalamus? |
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Definition
Forms a VAT
1. Ventromedial N.
2. Arcuate N.
3. Tuberal N. |
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Term
| Which nuclei comprise the mammillary region of the Hypothalamus? |
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Definition
1. Mammilary N.
2. Post hypothalamic N. |
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Term
| Each region of the hypothalamus divided into ____ and _____ areas. |
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Definition
| Medial and lateral areas. separated by fornix. |
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Term
| What is found in the medial and lateral areas of the hypothalamus? |
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Definition
Medial - all nuclei of the hypothalamus.
Lateral - No discrete nuclei - clusters of cells. Region consists primarily of axons - especially medial forebrain bundle. |
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Term
| Most tracts to the hypothalamus have what direction? |
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Definition
|
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Term
| Hypothalamus overall, interacts with 3 regions of the brain which are? |
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Definition
1. Thalamus - sensory interpretation
2. Limic - emotion
3. Midbrain - regulation of ANS. |
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Term
| Most neural input and output to hypothalamus occurs primarily via? |
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Definition
| Medial forebrain bundle (MFB) confined to the lateral area. |
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Term
| The hypothalamo-hypophyseal portal system called? |
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Definition
| Adenohypophysis (anterior pituitary gland) |
|
|
Term
| The APG (anterior pituitary gland) has what main function? |
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Definition
| Most of the endocrine glands are regulated by hormones from the APG. |
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Term
| Hormones released by the APG are under control of? |
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Definition
| Releasing factors - which are peptides. |
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Term
| Releasing factor (Peptides) are synthesized where? Go where? |
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Definition
| Synthesized: Parvicellular region - transported down axons of these neurons to median eminence (base of hypothalamus) where they are released from nerve endings into hypophyseal portal system. |
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Term
| What is the hypophyseal portal system? |
|
Definition
| Highly fenestrated capillary network located in median eminence, arises from superior hypophyseal artery. Factors released here transported down long portal vessels to adenohypophysis, here released again onto cells of anterior pituitary gland, which in turn releases hormones to general circulation via drainage to cavernous sinuses. |
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Term
| Endocrine glands respond how? |
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Definition
| Serve as targets and release hormones. Hormones of peripheral endocrine glands enter the blood and in addition to peripheral action "feedback" and influence the CNS and medial hypothalamus. |
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Term
| Posterior pituitary gland called? |
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Definition
|
|
Term
| Which nuclei transmit to the posterior pituitary gland? |
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Definition
| Supraopitc and paraventricular nuclei in hypothalamus. Synthesize vasopressin and oxytocin. Paraventricular nuclei seems to be most important. |
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Term
| Which cells of the nuclei secrete peptides to the neurohypophysis (posterior pituitary gland)? |
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Definition
| Magnocellular portion of paraventricular nuclei. |
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Term
| Peptides destined for the neurohypophysis change how? |
|
Definition
| They are secreted as 9-amino acid peptides (cleaved from pro-hormones within vesicles). Peptides are transported down the axons of neurons, released from nerve endings in neurohypophysis. Oxytocin and vasopressin released in NPHS and enter capillary bed from inferior hypophyseal artery - from here enter general circulation. |
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|
Term
| What is the function of oxytocin? |
|
Definition
| Released as peptide from magnocellular portion of paraventricular and supraoptic nuclei. Causes contraction of myoepithelial cells of mammary glands leading to milk ejection. Increases the amplitude of contraction of gravid uterus. |
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Term
|
Definition
Supraoptic and paraventricular nuclei (magnocellular portions) secrete VP AKA ADH (anti-diuretic hormone). Functions to:
1) maintain body water, increases water uptake in renal collection tube.
2) increases vasoconstriction.
3) Kidney is the principal target - increases membrane permeability to water.
4. responds directly to osmotic stimuli or [Na].
5. Vasopressor in nerves increases firing (secretion) in response to hyperosmotic blood, decreases firing when plasma [water] is high. |
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|
Term
| Tissue osmolarity has what impact on vasopressin secrition? |
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Definition
| Magnocellular regions in supraoptic and paraventricular nuclei have osmoreceptors that are sensitive to plasma osmolarity and [Na]. when activated - increase release of vassopressin. |
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Term
| Vascular volume has what impact on vasopressin secretion? |
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Definition
| Pressure receptors found in cardiovascular system (r.atrium, walls of great veins, aortic arch, carotid sinus, kidney) send feedback info via reflex arcs in brainstem. Hypothalamus has overriding control over these brainstem mechanisms and can release vasopressin. |
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Term
| How is the hypothalamus involved in regulation of body temperature? |
|
Definition
Via the Anterior and Posterior nuclei of hypothalamus.
1. Anterior Nuclei is "anti-heat", and dilates the skin of blood vessels, promotes seeking cooler environment,
2. Posterior nucleus is "pro-heat" - constriction of blood vessels, shivering, promotes seeking a warmer environment. |
|
|
Term
| How is the body's temperature "set point" changed? |
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Definition
| Systemic pyrogens induce macrophages to release IL-1. Il-1 acts on hypothalamus to raise the set point. |
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|
Term
| How is body temperature decreased? |
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Definition
| Anti-pyretic area found in region just anterior to the hypothalamus near anterior commissure. Area is stimulated by aspirin and counteracts fever. |
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Term
| This area of the hypothalamus controls "satiety", or inhibits overeating. |
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Definition
| Ventromedial nucleus of tuberal region, when stimulated, suppresses hunger. A lesion in this area can lead to HYPERPHAGIA. ** ventroMEDIAL = "To MUCH food...quite eating." |
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Term
| This area of the hypothalamus, when stimulated, leads to hunger, feeding behavior. |
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Definition
| Lateral "feeding center" - fiber tracts in lateral hypothalamus (remember no discrete nuclei are located here) Lesion here leads to aphagia, or weight loss. ** Lateral = LONG FOR FOOD. |
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Term
| Circadium rhythm "clock cells" are located where? |
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Definition
| In the suprachiasmatic nucleus - supraoptic region of hypothalamus. Lesion here will result in loss of normal cyclic variation of body function. |
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Term
| How is the hypothalamus related to emotional behavior. |
|
Definition
Same areas for feeding centers. Ventromedial nuclei - when activated - leads to placid behavior, decreased anxiety. A lesion here would result in excitable / aggressive behavior.
The Lateral areas of the hypothalamus - stimulation of these fiber tracts - leads to stimulation of the individual - increased aggressive behavior. |
|
|
Term
| Rare-autosomal recessive condition characterized by excessive deposits of calcium in skin and some areas of the brain - especially the amygdala. |
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Definition
|
|
Term
| This disease is characterized by rapid, jerky movements of fingers, hands, sometimes whole extremity. |
|
Definition
|
|
Term
| What is the cause of Huntington's chorea? |
|
Definition
| Loss of GABAergic neurons in caudate nucleus as well as cerebral cortex (intellectual and mental defects). Autosomal dominant inheritance. HD gene is involved in protein missfolding. Onset 30-50 yoa with death in 10-20 years. Choreiform - contralateral limb. Dopamine antagonists partly successful - L-DOPA makes worse. |
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Term
| Huntington's chorea involves loss of GABAergic cells in which areas of brain? Why are movements over expressed, then under expressed? |
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Definition
Striatum and other areas - essentially removes inhibition of globus pallidus via striatom inhibitory neurons.
1) With degeneration - striatum neruons fire spontaneously - contralateral spontaneous movements.
2) Once dengeneration complete - nothing inhibits globus palisus, so thalamus continually inhibited - intended movements cannot be expressed. |
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Term
| Patient demonstrates jagged or disarticulated movement when asked to touch finger to nose. This is called? |
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Definition
| Dysmetria - inaccuracy in rate and range of movement (undershoot/overshoot). Possible lesion to cerebro-cerebellum. "movement planning". |
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Term
| Patient is unable to maintain coordinated rhythm of alternating the turning of his hand palmside up and down on a table. |
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Definition
| Dysdiadochokinesia - planning difficulty possibly from lesion to cerebro-cerebellum. Inability to perform rapid alternating movements - cerebellar ataxia. Also seen in MS. |
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Term
| Patient demonstrates writhing movements of face and tongue, can be caused by antipsychotic drugs that block DA receptors. |
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Definition
| Tardive dyskinesia - involves the basal ganglia. |
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Term
|
Definition
| Basal ganglia disorder - patient shows slow, worm-like writing of fingers and hands. |
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Term
| Patient shows wildly, uncontrolled flinging of extremities. |
|
Definition
| Hemiballismus - Degeneration of subthalamic nucleus, usually confined to upper limbs (contralateral to lesion). Subthalamic nucleus is a target for treatment. |
|
|
Term
| Parkinson's disease is characterized by? Caused by? |
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Definition
| Charact: hypokinesia and hyperkinesia. Caused: degeneration of dopaminergic cells in Substantia Nigra compacta (SNc). |
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Term
| Hypokinesia associated with Parkinson's disease is caused by? |
|
Definition
| Loss of dopaminergic neurons that synapse on excitatory receptors. Makes it difficult for cortical neurons to activate striatal neurons. |
|
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Term
| Hyperkinesia associated with Parkinson's diseases caused by? |
|
Definition
| Hyperkinesia: loss of subset of dopaminergic neurons in Substantia Nigra compacta that synapse on inhibitory receptors in striatum spiny neurons. Loss of inhibition = spontaneous activity and unintended movements. |
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Term
| Type of tremor associated with cerebellar damage where motion is cyclic while moving towards object. |
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Definition
|
|
Term
| Movement that may result from unilateral damage to subthalamic nucleus? |
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Definition
|
|
Term
| Contains subnuclei critical for perception and recognition of fear. |
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Definition
|
|
Term
| Abnormal dance-like movement often associated with Huntington's disease. |
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Definition
|
|
Term
| A posterior pituitary hormone important for mineral and fluid balance. |
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Definition
|
|
Term
| Possible sign of flocculonodular damage. |
|
Definition
|
|
Term
| The neurotransmitter present in nigrostriatal projections that is lost in Parkinson's disease. |
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Definition
|
|
Term
| Provides major input to globus pallidus. |
|
Definition
|
|
Term
| Ratchetlike interruptions of tone associated with Parkinson's disease. |
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Definition
|
|
Term
| Lesions in lateral and intermediate cerebellum cause this type of ataxia. |
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Definition
|
|
Term
| Truncal ataxia associated with vermal dysfunction. |
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Definition
|
|
Term
| Neurotransmitter of cerebellar purkinje cells. |
|
Definition
|
|
Term
| Cerebellar hemisphere with predominant output to thalamus and motor cortex. |
|
Definition
|
|
Term
| Hormone secreted by adipocytes and important for body weight homeostasis. |
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Definition
|
|
Term
| Dopamine projection from ventral tegmentum to accumbens and basal forebrain important for motivation and pleasure. |
|
Definition
|
|
Term
| Abnormal rhythm and timing of movements. |
|
Definition
|
|
Term
| Striatal nucleus with outputs important for eye movements. |
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Definition
|
|
Term
| Term for slowed movement. |
|
Definition
|
|
Term
| Controlled by parvocellular neurons in hypothalamus via anterior pituitary releasing factor. |
|
Definition
|
|
Term
| What is the significant difference between cerebellum and basal ganglia regarding inputs? |
|
Definition
Cerebellum - receives feedback from periphery.
Basal ganglia - no feedback from periphery - essential for initiating movements. |
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Term
| Cerebellar peduncles - what are their names and associated functions? |
|
Definition
1. Superior - Brachium conjunctivum - major output. Efferents from Dentate and interposed nuclei and some from Fastigial.
2. Middle - Brachium pontis - only input from cerebral cortex via contralateral pontine nuclei.
3. Inferior - restiform body - input and output. Main source of input from periphery. |
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|
Term
| Main source of input to cerebellum from periphery travels through which peduncle? |
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Definition
| Inferior cerebellar peduncle. |
|
|
Term
| The vestibulo cerebellum is comprised of? Fxn? |
|
Definition
| Flocculonodular lobe - most primitive (archi) responsible for equilibrium and balance. Lesion here can result in nystagmus. |
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Term
| Spinal (intermediate - vermis) cerebellum is comprised of? Fxn? |
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Definition
| Vermis - adjacent medial portions (paleo). Responsible for execution of movement proximal and distal limbs. Highly dependent on feedback from receptors in muscle - cuneocerebellar and dorsal spinocerebellar tracts. Samples motor command during movment and compares with feedback from proprioception. |
|
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Term
| Lateral hemisphere (cerebrocerebellum)of cerebellum comprised of? Fxn? |
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Definition
| Most lateral edges - Neo - responsible for movements. Receives no feedback from periphery. Most highly evolved - very important for speech. No motor paths directly influenced. Communicates between the association motor cortex and the primary motor cortex. |
|
|
Term
| What is the cuneocerebellar tract? |
|
Definition
| Peripheral afferents to spinocerebellum - from the hands. |
|
|
Term
| What is the dorsal spinocerebellar tract? |
|
Definition
| Peripheral afferents to spinocerebellum from the legs. |
|
|
Term
| Basal ganglia are involved in, responsible for what? |
|
Definition
| Planning and initiating movements - not the execution. |
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|
Term
| What are the deep cerebellar nuclei and what are their projections / functions? |
|
Definition
Lateral to medial
1. Dentate = to motor and pre-motor - motor planning.
2. Interposed (emboliform/globase) to lateral descending systems - motor execution.
3. Fastigial - to medial motor systems - motor execution.
Vestibulo cerebellum - to vestibular nuclei - balance and eye movement. |
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Term
| Lesions in the vestibulocerebellum could result in? |
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Definition
| Difficulty standing - compensate with feet widely spread. Also could have nystagmus. |
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|
Term
| Vestibulocerebellum receives inputs from? |
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Definition
| semi-circular canals and otoliths. maintains equilibrium and balance, also controls eye movements. Mediated through vestibular nuclei. |
|
|
Term
| Inputs to cerebrocerebellum arrive via? |
|
Definition
| Inferior cerebellar peduncle. |
|
|
Term
| Outputs from the medial and lateral vestibular nuclei controlling eye movements travel in what tract? |
|
Definition
| Medial vestibulospinal tract. |
|
|
Term
| Outputs from the medial and lateral vestibular nuclei controlling Axial and Limb muscles travel in what tract? |
|
Definition
| Lateral Vestibulospinal tract. |
|
|
Term
| Medial and lateral vestibular nuclei receive inputs from? |
|
Definition
1- otoliths and semicircular canals.
2 - directly from flocculonodular lobe.
3 - from FN lobe via fastigial nucleus - also send signals back to FN lobe via fastigial nucleus. |
|
|
Term
| Overall functions of the spinocerebellum (intermediate) cerebellum? |
|
Definition
| Regulate body and limb movements - compare feedback from ongoing movement with original command from motor cortex. |
|
|
Term
| Input sources to the spinocerebellum? |
|
Definition
1. Proprioceptive afferents.
2. Collaterals from nerves carrying commands from cerebral motor cortex. |
|
|
Term
| Afferent tracks that reach the spinocerebellum? |
|
Definition
1. Cuneocerebellar tract from upper limbs, arising from external (accessory) cuneate nucleus.
2. Dorsal spinocerebellar - lower limbs, arising from dorsal nucleus of clarke. |
|
|
Term
| What is the function of the relay nuclei in the brainstem? |
|
Definition
| Inform cerebellum about intended movement. Cerebellum compares information sampled from intended movement with information in form of feedback from actual movement. |
|
|
Term
| What is the function of the RED nucleus? |
|
Definition
| Assists motor cortex in supporting distal (especially flexor) muscles, via Rubral Spinal Tract. |
|
|
Term
| Which brainstem relay nuclei are involved with cerebellum / motor function? |
|
Definition
1. Pontine nuclei
2. Lateral reticular nuclei
3. Inferior olivary nuclei. |
|
|
Term
| Principal input to cerebro-cerebellum comes from what relay nuclei? |
|
Definition
|
|
Term
| Output from cerebrocerebelllum goes to? |
|
Definition
|
|
Term
| From dentate nucleus, the output goes where? |
|
Definition
| To the VA/VL thalamus - then to primary motor cortex. |
|
|
Term
| Input to the cerebrocerebellum from the pontine relay nuclei travel through which peduncle? |
|
Definition
|
|
Term
| Output from the Dentate nucleus to the thalamus travels through? |
|
Definition
| Superior Cerebellar peduncle. |
|
|
Term
| Patients with lesions of the lateral hemisphere present with (cerebrocerebellum)? |
|
Definition
a. Delays in initiating movements
b. irregular timing of movement components - decomposition of movements. Have to "think out each movement of arm".
Cognitive: estimating time lapse, spatial or temporal movements. |
|
|
Term
| Overall function of the cerebrocerebellum? |
|
Definition
| Planning a movement before it is executed. Programming the correct timing and articulation of muscles well before primary motor cortex has issued command. Primary motor cortex is area 4. |
|
|
Term
| What are the 5 types of cells in the cerebellum? |
|
Definition
1. Purkinje = output, largest, inhibitory, GABA
2. Granule = input, always excitatory
3. Stellate = interneuron - inhibitory
4. Basket = interneuron - inhibitory
5. Golgi = interneuron - inhibitory. |
|
|
Term
| What are the cell layers of the cortex? |
|
Definition
1) Molecular layers (axons of granule, basket, and stellate cells)
2) Purkinje
3) Granular |
|
|
Term
| Granule cells of the cerebellum are activated by? |
|
Definition
| Mossy fibers - bring information from muscles and joint receptors via cuneocerebellar and dorsal spinocerebellar tracts. |
|
|
Term
|
Definition
| Climb up and bifurcate in the molecular layer, becoming telephone lines on telephone poles (purkinje cells). |
|
|
Term
| What is the role of climbing fibers? |
|
Definition
| Excitatory input from inferior olivary nucleus. Climbing fibers like vines, wrap thrmeselves around cell body and dendrites of purkinje cell. Much greater excitatory influence on Purkinje cell than granule cell. |
|
|
Term
| Compare the differences between climbing fibers and granule cells. |
|
Definition
Function: Climbing (major excitatory), Granule (minor excitatory).
Spikes: Climbing (large-dominating complex) Granule - simple spikes - small steady. |
|
|
Term
| How do climbing fibers and granule cells interrelate? |
|
Definition
| May provide timing signal for subset of purkinje fibers. Permanently change response in a subset of purkinje cells to granule cell input, possible substrate for learning a skill. |
|
|
Term
| Characterize the status of deep cerebellar nuclei. |
|
Definition
| Tonically active - mossy fibers and climbing fibers send collaterals. Nothing enters or leaves cerebellum without saying hello to deep cerebellar nuclei. |
|
|
Term
| Purkinje cells have what affect on Deep Cerebellar nuclei? |
|
Definition
| Cluster of Purkinje cells will use inhibition to "script away" tonic activity of Deep Cerebellar Nuclei. |
|
|
Term
| How are "clusters" of Purkinje cells activated? |
|
Definition
| Activation of a "beam" of parallel fibers (from granule cells) granule from mossy - represent peripheral feedback from joint or muscles around joint. |
|
|
Term
| Overall function of basal ganglia? |
|
Definition
| Initiate movement toward a goal. Do not communicate directly with motor neurons or receive feedback from periphery. So they ARE NOT involved with direction or velocity of movement. Even before a motor command is issued - intention to move is provided to BG. |
|
|
Term
| What areas of cerebral cortex provide input to BG? |
|
Definition
| Nearly all areas EXCEPT primary visual and auditory cortices. |
|
|
Term
| Basic circuit of Basal Ganglia. |
|
Definition
1. Several cortices except vision and auditory, provide input to BG.
2. BG projects to thalamus.
3. Thalamus project to area 4 of primary motor cortex.
4. Primary motor cortex projects via corticospinal tract to contralateral side of body. |
|
|
Term
| Basal ganglia consist of 5 paired nuclei which are? |
|
Definition
Nucleus with their meaning
1. Caudate - tail
2. Putamen - shell
3. Globus Pallidus - pale ball
4. Substantia Nigra - dark substance
5. Subthalamic Nucleus - beneath the thalamus |
|
|
Term
| Caudate nucleus projects to? |
|
Definition
|
|
Term
| The main area of contact between the caudate and putamen is the? |
|
Definition
| Nucleus accumbens. The caudate and putamen are separated partially by the internal capsule. |
|
|
Term
| Corpus striatum is comprised of the? |
|
Definition
| Caudate and Putamen. Means - body of lines. |
|
|
Term
| What separates the caudate and putamen? |
|
Definition
| Striations consisting of tracts of the anterior limb of internal capsule. |
|
|
Term
| The lenticular nucleus consists of? |
|
Definition
| Putamen and globus pallidus - together form a "LENS-LIKE" structure. |
|
|
Term
| Substantia nigra is located where? |
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Definition
| Rostral midbrain, between cerebral peduncle and red nucleus. Globus pallidus and substantial nigra were together but are separated by internal capsule during development. They share many of the same characteristice. |
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Term
| What is the direct loop of the basal ganglia? |
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Definition
| When activated - leads to initiation of movement. |
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Term
| What is the indirect loop of the basal ganglia? |
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Definition
| When activated, prevents spontaneous movements. |
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Term
| What is the balance between the direct and indirect loops of the basal ganglia? |
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Definition
| Normally motor programs are inhibited via the indirect loop. When movement is intended, the direct loop originating in the cortex, takes over. |
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Term
| How does the direct loop of the basal ganglia function? |
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Definition
All basal ganglia are largely inhibitory EXCEPT Subthalamic nuclei.
1. In anticipation of movment - cortex excites the striatum (caudate/putamen)
2. Striatum inhibits globus palidus, normally GP has an inhibitory hold on thalamus.
3. With GP inhibited by striatum it releases inhibitory hold on VL/VA of thalamus.
4. Thalamus becomes disinhibited - results in thalamus activating area 4 of cortex - net result is initiation of movement. |
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Term
| How does the indirect loop for the basal ganglia function? |
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Definition
Subthalamic nucleus = sculpting precise intended movement.
1. When stimulated, subthalamic nucleus releases glutamate - stimulates GP to up its inhibitory input on thalamus.
- Net effect is when subthalamic nucleus is activated, thalamus is inhibited, blocks unwanted movements. |
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Term
| With regard to the striatum, if active it does what? Inactive? |
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Definition
Active: Supports movement - inhibits GP.
Inactive: blocks movement - allows GP to be active - inhibiting thalamus. |
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Term
| What is the importance of dopamine cells in the SNc (Substantia Nigra Compacta)? |
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Definition
| Modulatory effect. Dopamine released onto cells in striatum can have inhibitory or excitatory effects, depends on which subset of nigro-striatal neurons is active. All depends on type of dopamine receptors on striatal dendrites. |
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Term
| Loss of substantia nigra cells in parkinson's disease has what affect? |
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Definition
| Loss of dopamine prevents some movements - hypokinesia, while allowing unwanted movements (hyperkinesia). |
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Term
| What are the two parts of the substantia nigra? |
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Definition
1. Pars compacta - dopaminergic neurons
2. Pars reticulata - reticulated appearance, with large number of axons coursing through this area on way to VA/VL of thalamus. Sends inhibitory output to thalamus Va/Vl. Acts like GPi, both SNr and GPi are inhibitory to thalamus. |
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Term
| What to areas of the basal ganglia are similar in embryonic origin, and function? |
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Definition
| Globus pallidus and substantia nigra. Specifically, GP (internal) and SNr (substanta nigra reticulata) are inhibitory to thalamus. |
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Term
| What does the Substantia Nigra compacta produce? |
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Definition
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Term
| Primary input to the basal ganglia is via? |
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Definition
| Several areas of the cerebral cortex. |
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Term
| Primary output of the basal ganglia is to? Via? |
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Definition
| The VA/VL of the thalamus, via the Globus pallidus (internal) and Substantia Nigra reticulata. |
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Term
| What is the main type of neuron found in the Striatum? |
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Definition
| Medium spiny neuron (found in caudate and putamen). |
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Term
| The medium spiny neurons of the striatum secrete what? |
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Definition
| GABA (inhibitory) on targets of Globus pallidus (internal and external) and Substantia nigra reticula. |
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Term
| The medium spiny neurons of the striatum receive input from? |
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Definition
| Several sources, including SNc (dopaminergic). |
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Term
| What is the ratio of cortical pyramidal cells to spiny neurons? |
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Definition
| Each pyramidal cell contacts MANY Medium spiny neurons - implying broad cortical influence. Each spiny neuron receives input from MANY cortical cells. |
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Term
| Medium spiny neurons of the basal ganglia fire when? |
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Definition
| When there is an "intention" to move but PRIOR TO the actual movement. |
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Term
| Overall function of the basal ganglia with regard to movement? |
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Definition
| Initiate intended movement and keep unintended movement in check. |
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Term
| What is lead pipe rigidity? |
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Definition
| Resistance met by clinician in passively moving a limb in any direction around joint. Contrast this to "spastic rigidity" - velocity of movement not a factor and all muscles involved not just antigravity. |
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Term
| What is cogwheel rigidity? |
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Definition
| Limb is forced - pt displays tremor at rest. Rigidity observed is released and engaged at 3hz tremor frequency. |
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Term
| What is the traditional therapy for Parkinson's disease? |
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Definition
| L-DOPA, dopamine precursor that passes the blood brain barrier. Given with carpidopa a decarboxylase inhibitor that doesn't pass BBB - conteracts peripheral side effects of L-dopa. |
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Term
| Without the limbic system, the hypothalamus cannot what? |
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Definition
| Initiate directed emotional behavior. |
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Term
| Two major functional components of the limbic system? |
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Definition
1. Hippocampus - memory formation.
2. Amygdala - essential to provide emotional components to memory. |
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Term
| All excitatory pathways in basal ganglia are? |
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Definition
|
|
Term
| All inhibitory pathways in Basal Ganglia are? |
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Definition
|
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Term
| The Globus pallidus projects to the thalamus via 2 routes? |
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Definition
1. ANSA lenticularis
2. Lenticular fasciculus |
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Term
|
Definition
| Projections for the Globus pallidus to the thalamus. |
|
|
Term
|
Definition
| Projections from the globus pallidus to the thalamus. |
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Term
| Cholinergic effects on the cortex and hippocampus are generally? |
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Definition
| Facilitatory. Remember that the excitatory NT of the CNS is Glutamate. |
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Term
| Norepinephrine is released by which nucleus? |
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Definition
|
|
Term
| Serotonin is released by what nuclei? |
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Definition
|
|
Term
| Dopamine is released by which nuclei? |
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Definition
|
|
Term
| Acetylcholine is released by which nuclei? |
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Definition
| Medial septal nucleus, Nucleus of diagonal band, and pedunculopontine nucleus. |
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Term
| The ventrolateral preoptic nucleus has what effect on sleep? |
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Definition
| Inhibits the ativity of ARAS, thereby promoting sleep. |
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Term
| Orexin located where? Does what? |
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Definition
| Orexin containing neurons in the posterior lateral hypothalamus excite the ARAS, thereby promoting arousal. Histamine neurons in the tuberomammillary nucleus maintain the alert state. |
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Term
| Physiology of NON-REM sleep? |
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Definition
| GABAaergic neurons in the ventral preoptic area inhibit neurons in ARAS, including posterior hypothalamic OREXIN neurons, as well as histamine (tuberomammillary nucleus, serotonin, noradrenalin, and dopamine, as well as brainstem cholinergics. |
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Term
| In wakefulness, what is the status of NTs? |
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Definition
1) Cholinergic nuclei - ACH - Active
2) Locus coeruleus - norephin - Active
3) Raphe nucleus - Seratonine - Active
4) Tuberomammillary - OREXIN - Active. |
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Term
| In non-rem sleep, status of NTs? |
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Definition
1. Cholinergic - ACH - Decreased
2. Raphe - seratonin - decreased.
3. Locus ceruleus - Noreph - Decreased. |
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Term
| In REM sleep ON, what is the status of NTs? |
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Definition
1. Cholinergic - ACH - Active
2. Raphe - seratonin - Inactive. |
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|
Term
| In REM Sleep - OFF, what is the status of NTs? |
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Definition
| 1. Locus ceruleus - ACTIVE. |
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Term
| Lack of sleep that causes performance deficits and irritability. |
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Definition
|
|
Term
| Collapse of pharynx causes sleep disruption due to vigorous inhalation. |
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Definition
|
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Term
| What is a possible cause of Narcolepsy? |
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Definition
| Decrease in the number of orexin-containing neurons in the hypothalamus, or a mutation in the orexin receptor gene. |
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Term
| What is the WADA procedure? |
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Definition
| Determines language dominant hemisphere. Inject fast acting short-lived barbiturate into the carotid artery; preferentially effects ipsilateral hemisphere. Rapid paralysis and loss of sensation from contralateral body. Unable to speak upon request if injection affects the dominant hemisphere. |
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Term
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Definition
| The language function of the non-dominant hemisphere. the rhythmic and musical quality of speech to inflection. Largely responsible for the affective qualities of speech. |
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Term
| Expressive and comprehensive aprosodia? |
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Definition
| The inability to generate or understand the emotional quality of speech. Caused by damage to areas analogous to Broca's and Wernicke's in the right or "non dominant" hemisphere. |
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Term
|
Definition
| Partial or complete loss of language abilities due to brain damage. |
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Term
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
| Impaired ability to repeat words, damage to arcuate fasciculus. |
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|
Term
| Transcortical motor aphasia. |
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Definition
| Poor fluency, repetition and comprehension relatively intact. Poor naming and writing. Caused by an ACA-MCA watershed infarct. |
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|
Term
| Pure word blindness, circuitry of alexia without agraphia. |
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Definition
| Ability to read is impaired, but ability to write is intact. Caused by lesions to the left occipital cortex that also involve the corpus callosum. This is paired with right homonomous heminaopia. Words cannot be seen by the left hemisphere; words seen by the right hemisphere, but cannot be communicated to the language centers in the left hemisphere due to damage to the corpus callosum. |
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Term
| Function of the non-dominant (typically right) hemisphere is that of directing our? |
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Definition
| Attention. Regions of the right parietal lobe appear to be responsible for focusing our attention and awareness of the left side of our environment and even our own body. |
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Term
| Non-declarative memory is subdivided into three areas: skills & habits, conditioned reflexes, emotional. Which controls each? |
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Definition
1. Skills and habits: Striatum
2. Conditioned reflexes: Cerebellum
3. Emotional: Amygdala |
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Term
| Alzheimer's disease is caused by the inappropriate processing of? |
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Definition
| Amyloid precurser protein (APP), a transmembrane protein of unknown function. Causes formation of insoluble aggregates of B-amyloid protein. |
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Term
| Posterior lobe of the pituitary is considered to be brain or gland? |
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Definition
| Part of the Brain. The anterior pituitary is a gland. |
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Term
| Anterior lobe of the pituitary is considered to be brain or gland? |
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Definition
| Gland. Posterior is considered part of the brain. |
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Term
| Axons of what neurons feed to the posterior pituitary? What do they do? |
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Definition
| Axons of hypothalamic MAGNOCELLULAR neurons extend into the posterior pituitary and secrete OXYTOCIN and VASOPRESSIN - Directly into the capillary blood within the posterior lobe. |
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Term
| Release of Vasopressin is mediated by? |
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Definition
| Brain osmoreceptors that sense cellular dehydration and by the peptide hormone angiotensin II, in response to decreased blood volume. Vasopressin reduces fluid loss and angiotension increases blood pressure and stimulates thirst and salt appetite. |
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Term
| What controls the function of the Anterior pituitary? |
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Definition
| It is a gland, Releasing factors are produced by PARVOCELLULAR neurons in the hypothalamus and released into capillaries at the base of the pituitary stalk (median eminence). These stimulate release of anterior pituitary hormones into the systemic blood that then act on other organs and glands. |
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Term
| What are some hormones of the anterior pituitary gland? |
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Definition
| LH, FSH, ACTH, TSH, GH, Prolactin. |
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Term
| What is the function of CRH (Corticotropin Releasing Hormone)? |
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Definition
| Secreted by hypothalamic PARVOCELLULAR neurons, causes release of ACTH from Ant. Pituitary, which stimulates release of cortisol from the adrenal cortex. |
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Term
| Arcuate nucleus of Hypothalamus functions to? |
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Definition
| sense circulating substance that signal energy balance i.e. (leptin, insulin, ghrelin), also receives input from vagal sensory sites and glucoregulatory neurons in hindbrain. Contains potent orexigenic and anorexigenic neuropeptides. |
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Term
| Lateral hypothalamus contains? |
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Definition
| Orexin - peptide involved in appetite and REM sleep. |
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Term
|
Definition
| Signals amount of adiposity. Binds to receptors in the arcuate nucleus of Hypothalamus. Leptin reduces food intake and increases metabolic rate. Animals with lesion to arcuate nucleus, (contains leptin binding sites), results in increase body weight and food intake. |
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Term
|
Definition
| Feeding. Increased feeding coincides with increased levels of Ghrelin. Lesion of arcuate nucleus abolishes the stimulation of feeding by ghrelin. |
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Term
| Suprachiasmatic nucleus produces proteins that do what? |
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Definition
| Inhibit further transcription, hence generating a negative feedback mechanism that allows gene expression to cycle up and down over 24 hour cycles. Entrained by projections of melanopsin neurons. |
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|
Term
| Major structures of the limic system? |
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Definition
1) Cingulate gyrus, frontal lobe, basal forebrain.
2) Amygdala
3) Hypothalamus. |
|
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Term
| Emotions consist of two components which are? |
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Definition
Emotional experience: perception of emotion, controlled by neocortex with inputs from the limbic system and other structures.
Physiological component: emotional expression, controlled by somatic nervous system, ANS, and the hypothalamic neurosecretory system. |
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Term
| What is Kluver-Bucy Syndrome? |
|
Definition
Lesion of the temporal lobe and underlying structures (amygdala and hippocampus) causes:
1. Hypersexuality
2. Loss of hostility
3. Loss of fear with taming effect
4. Flattened emotion
5. Visual recognition problems.
6. Odd oral behaviors. |
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Term
| What affect does serotonin have on limbic structures? |
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Definition
| Serotonin terminals innervate limbic structures and modulate aggression. Serotonin antagonists increase aggression. Deletion of serotonin receptor gene increases aggression. |
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Term
| What is the mesolimbic dopamine system? |
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Definition
| Especially important for motivation and reinforcement. System originates with dopamine cell bodies in the midbrain, just medial to those in the substantia nigra. These dopamine cells project to the limbic forebrain structures (nuc. accumbens) not to the striatum. |
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Term
| What systems are essential for positive emotions? |
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Definition
| Brain norepinephrine and dopamine systems and their limbic targets. |
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Term
| What is the mechanism by which cocaine gives a euphoric feeling? |
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Definition
| Blocks the reuptake of Norepinephrine and dopamine, so there is more to stimulate the receptors in the limbic system. |
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Term
| These drugs are central players in treatment of mental illness by affecting the limbic system. |
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Definition
| Norepinephrine, Dopamine, Serotonin. |
|
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Term
| What is this treatment for Parkinson's "Pallidotomy"? |
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Definition
| Stereotaxically- placed lesion that disrupts inhibitory output pathway from the globus pallidus to ventral lateral nucleus of thalamus. |
|
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Term
|
Definition
| Sustained distorted positions of limbs, face, or trunk. |
|
|
Term
| Midline cerebellar lesions mainly cause? |
|
Definition
| Truncal ataxia, "unsteady gait", abnormal eye movements (nystagmus), vertigo with accompanying nausea and vomiting. |
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|
Term
| Lateral lesions of the cerebellum mainly cause? |
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Definition
| Ataxia of the limbs (appendicular ataxia). |
|
|
Term
| What is the "pallidum" with regard to basal ganglia? |
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Definition
| Consists of the Globus pallidus and substantia nigra zona reticulata. |
|
|
Term
| Caudate and putamen receive input from widespread cortical areas via mainly what NT? |
|
Definition
| Glutamine - glutamatergic. |
|
|
Term
| Caudate inputs mainly from? |
|
Definition
| Frontal Eye Fields and visual association areas. |
|
|
Term
| Putamen inputs mainly from? |
|
Definition
| Somatosensory cortex, SMA and PMA, association cortex. |
|
|
Term
| Outputs for Caudate and Putamen? |
|
Definition
Caudate = output governing eye movements.
Putamen = output mainly limbs. |
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|
Term
| MPTP - synthetic narcotic street drug does what? |
|
Definition
| Structurally similar to dopamine. Transported into dopaminergic neurons by dopamine transporter. MPP destroys mitochondria, Hence dopamine cells in the substantia nigra die, causing signs similar to Parkinson's disease. |
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Term
| Corticopontocerebellar projections terminate in the ips/cont pontine nuclei? Pontine nuclei then project to ips/cont cerebellum? |
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Definition
| Terminate in ipsilateral pontine nuclei, project to contralateral side of cerebellum. |
|
|
Term
| Deep cerebellar nuclei project to thalamus and cortex on the ips/cont side via the superior cerebellar peduncle? |
|
Definition
|
|
Term
| The inputs and outputs to the cerebellum result in cerebellar lesions producing contralateral/ipsilateral deficits? |
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Definition
| Ipsilateral deficits. (double crossing of inputs and outputs). |
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|
Term
| What is "fractured somatotopy" as related to the cerebellum? |
|
Definition
| Receptive fields in cerebellar cortex reveal multiple representations of the same body parts in different locations. |
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|
Term
| Basket cells in cerebellum serve to? |
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Definition
| Inhibit Purkinje cells flanking the parallel fiber beam from the granule cell, a type of surround inhibition. |
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