Term
| what are the 3 major tracts that would be affected by a lesion of the anterior spinal artery at the level of the medulla? |
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Definition
1. CN XII - hypoglossal nucleus
2. lateral corticospinal tract (medullary pyramids)
3. medial lemniscus |
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Term
| what is the effect of a lesion of the lateral corticospinal tract at the level of the medulla? explain |
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Definition
| loss of fine motor control on the contralateral side and spasticity (spastic hemiparesis); fibers cross at the motor decussation at the level of the lower medulla |
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Term
| what is the effect of a lesion of the hypoglossal nucleus at the level of the medulla? |
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Definition
| ipsilateral flaccid hemiparesis of tongue; when tongue is protruded will point in the direction of the lesion due to weakness on the affected side |
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Term
| what is the effect of a lesion of the medial lemniscus at the level of the medulla? |
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Definition
| contralateral loss of fine touch and proprioception from trunk and extremities.lesions above the sensory decussation will have effect on the contralateral side |
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Term
| what is the effect of a lesion of the UMN vs the LMN of the hypoglossal n? |
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Definition
UMN: will get hemiparesis on contralateral side of tongue; tongue deviates to opposite side
LMN: will get ipsilateral hemiparesis; tongue deviates to smae side as lesion
-UMNs cross and synapse on LMNs |
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Term
| what are the affected structures in medial inferior pontine syndrome (occlusion of the paramedian branches of basilar artery) at the level of the pons? |
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Definition
corticospinal tract
medial lemniscus
abducen nerve roots |
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Term
| what is the affect of a lesion at the level of pons on CNVI? |
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Definition
| ipsilateral lateral rectus paralysis - medial deviation of ipsilateral eye |
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Term
| what is the major blood supply to the brainstem? |
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Definition
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Term
| what is the effect of an UMN lesion of the facial nerve (VII)? |
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Definition
| contralateral facial m weakness below eyes; facial n branches innervating upper face receive bilateral UMN innervation so will retain function even if there is lesion on one side. lower face receives only contralateral UMN innervation |
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Term
| which cranial nerve is affected in paramedian midbrain (Benedikt) syndrome? what are the manifestations? |
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Definition
| the oculomotor (III) - lose ipsilateral innervation all mm; can only abduct (VI) and depress (IV) eye. Get fixed, dilated pupil (lose innervation of sphincter pupillae m) and ptosis (lev palpebrae sup m) |
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Term
| how do the manifestations of a lateral corticospinal tract lesion differ at the level of the spinal cord vs. in the pons? |
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Definition
-spinal cord: get ipsilateral loss of voluntary fine movements below level of lesion
-pons: get contralateral spastic hemiparesis |
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Term
| what structures form the walls and floor of the 3rd ventricle? |
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Definition
| thalamus and hypothalamus |
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Term
| anatomically speaking, what is the relationship between the massa intermedia and the 3rd ventricle? |
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Definition
| divides the 3rd ventricle into upper and lower channels |
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Term
| what fibers are running thru the internal capsule? |
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Definition
| mostly reciprocal connections b/w thalamus and cerebral cortex |
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Term
| what forms the lateral boundary of the diencephalon? |
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Definition
| fibers of the internal capsule |
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Term
| what is the role of the dorsal thalamus w/ regards to sensory and motor info to/ from cerebral cortex? |
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Definition
| it is the principal relay structure - i.e. sensory and motor information destined for ipsilateral cerebral cortex or descending from it must pass through dorsal thalmus (except olfactory info - passes thru only indirectly) |
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Term
| what is the main function of the dorsal thalamus? how is its function carried out? |
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Definition
-controls flow of info from periphery to cortex
-cortical axons project into dorsal thalamus and help "gate" info that reaches cerebral cortex - selective attention. |
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Term
| what are the two descriptions/terms used to refer to the parts of the brain in front of, and behing the central gyrus? |
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Definition
front half- expressive
back half - receptive |
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Term
| what part of the dorsal thalamus is connected to the primary somaticsensory cortex? name 2 tracts that ascend to somatosensory cortex via VPL. |
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Definition
ventral posteriolateral nucleus (VPL) and VPM in parietal lobe
-dorsal column/medial lemniscus and lateral spinothalamic (anterolateral system) |
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Term
| which nuclei in the dorsal thalamus is reciprocally connected to the primary auditory cortex in the temporal lobe? |
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Definition
| medial geniculate nucleus |
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Term
| which nuclei in the dorsal thalamus is reciprocally connected to the primary visual cortex in the occipital lobe? |
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Definition
| lateral geniculate nucleus |
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Term
| what part of the cerebral cortex is reciprocally connected to the pulvinar and lateral posterior nuclei of the dorsal thalamus? |
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Definition
| multimodal sensory association cortex fo the parietal, occipital and temporal lobes |
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Term
| what connects the primary motor cortex and motor association areas of the cerebral cortex to the dorsal thalamus? |
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Definition
| ventral anterior and venteral lateral nuclei |
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Term
| what is the function of the reciprocal connections b/w anterior and medial thalamic nuclei of the dorsal thalamus and the motor and limbic system of the cerebral cortex? |
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Definition
| to orchestrate coordinated and appropriate behavioral responses to sensory information |
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Term
| what dorsal thalamic nuclei are connected with the limbic lobe? |
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Definition
| anterior & lateral dorsal nuclei |
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Term
| what part of the cerebral cortex does the the medial dorsal nucleus of the dorsal thalamus communicate reciprocally with? |
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Definition
| frontal association cortex |
|
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Term
| what descending pathways start in the primary motor cortex? what thalamic nuclei will they synapse in? |
|
Definition
corticospinal and corticobulbar tracts
-ventral anterior and ventral lateral nuclei |
|
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Term
| name the 4 limbs of the internal capsule. what lobe of the cerebral hemispheres are associated with each? |
|
Definition
anterior limb - frontal lobe
posterior limb - parietal lobe
retrolenticular limb (LGN) - occipital lobe
sublenticular limb (MGN) - temporal lobe |
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Term
| the fibers of which tract run through the genu? |
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Definition
| fibers of corticobulbar tract |
|
|
Term
| what fibers run thru the posterior limb of the internal capsule? |
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Definition
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Term
| what is the largest nucleus of the ventral thalamus? |
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Definition
| subthalamic nucleus - it part of the circuitry of the basal ganglia |
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Term
| what is the blood supply to the anterior dorsal thalamus? |
|
Definition
| thalamoperforating artery |
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|
Term
| what vessel supplies the posterior thalamus and geniculate bodies? |
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Definition
|
|
Term
| what vessels supply the internal capsule? |
|
Definition
| br of the middle cerebral a (i.e. medial striate aa., lenticulostriate aa.) |
|
|
Term
| what are the origins of the anterior and posterior pituitary glands? |
|
Definition
posterior lobe: floor of the developing diencephalon
anterior lobe: floor of the developing oral cavity = Rathke's pouch |
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|
Term
| what are the main functions of the hypothalamus? |
|
Definition
-control of the pituitary gland
-control of the autonomic nervous system
-control of a variety of behaviors essential for survival - eating, sleeping, drinking, sexual behavior, parental behavior, aggression |
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Term
| what are the two axes along which the nuclei of the hypothalamus are organized? name the nuclei along each axis |
|
Definition
rostral to caudal axis:
preoptic, supraoptic, tuberal area, mammillary area
medial to lateral axis:
periventricular, medial, lateral |
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Term
| what are some of the subdivisions and functions of the preoptic area? |
|
Definition
-most rostral nucleus
-has medial and lateral preoptic area
-MPOA regulates male sexual behavior and parental behavior; neurons in this nucleus have receptors for estrogen and androgens
-LPOA: important in thermoregulation, heat dissipation, vasodilation, sweating |
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Term
| name three important nuclei in the supraoptic area. where is the supraoptic area in relation to other nuclei of the hypothalamus? |
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Definition
-paraventricular nucleus (PVN), supraoptic nucleus (SON), suprachiasmatic nucleus (SCN)
-located caudal to the preoptic nucleus |
|
|
Term
| what are the products and functions of the PVN and SON? |
|
Definition
-product oxytocin and vasopressin
-releases these peptides into capillaries of posterior pituitary - direct connection |
|
|
Term
| what is the function of the suprachiasmatic nucleus? |
|
Definition
-cells of SCN are circadian oscillators - entrain endocrine functions and behaviors to the 24 hour light-dark cycle.
-has connections from retina to SCN to IML to sup cervial ganglion and finally to pineal gland, where NE regulates melatonin synthesis |
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Term
| where is the tuberal area located? name two nuclei that are directly involved in control of the ant pituitary |
|
Definition
-right above pituitary stalk
-periventricular and arcuate neurons have receptors for many hormones and provide feedback regulation to trophic-hormone producing cells of the anterior pituitary |
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Term
| how do the periventricular and arcuate neurons control the release of hormones from the ant pituitary? |
|
Definition
-have receptors for many hormones
-provide feedback regulation via portal venous system that controls release of releasing hormones from anterior pituitary |
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|
Term
| what is the role of the ventromedial nucleus of the tuberal area? |
|
Definition
-controls female sexual behavior and aggression
-neurons express receptors for sex hormones |
|
|
Term
| what are the afferent and efferent connections of the mammillary bodies? |
|
Definition
input/afferent: hippocampus via fornix
output/efferent: anterior nucleus of thalamus |
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|
Term
| T/F: mammillary bodies are part of the limbic system |
|
Definition
|
|
Term
| what is the affect of damage to the mammillary bodies? |
|
Definition
| anterograde amnesia (Korsakoff's syndrome) |
|
|
Term
| what is the medial forebrain bundle? |
|
Definition
| the MFB runs through the lateral hypothalamic area (LHA) and contains ascending and descending fibers. It connects limbic areas, hypothalamus and brainstem |
|
|
Term
| what are the functions of the lateral hypothalamic area? |
|
Definition
-helps regulate autonomic function, sleep-wake cycles and arousal
-has major connections with the reticular formation and limbic system
- the MFB runs thru it, carrying ascending and descending fibers that connect limbic, hypothal and brainstem |
|
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Term
| name the hypothalamic nuclei that have endocrine functions and state their fxn |
|
Definition
-paraventricular and supraoptic: produce and release ADH and oxytocin into post pituitary
-preoptic: regulate release of gonadotropic hormone
-arcuate (tuberal nuclei): produce hypothalamic releasing factors |
|
|
Term
| what is the tuberoinfundibular tract? |
|
Definition
| this is the name of the tract by which tropic factors from the tuberal region of the hypothalamus cause hormones to be released by ant pituitary; this is an indirect endocrine fxn vs the direct function of the supraoptic and paraventricular nuclei which release hormones into the post pituitary directly via a hypothalamo-hypophyseal tract |
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|
Term
| which nuclei of the hypothalamus regulate autonomic fxns? |
|
Definition
anterior: thermal regulation (dissipation), stimulation of PS NS
posterior: thermal regulation (conservation of heat), stim of symp NS
suprachiasmatic: mediates circadian rhythms |
|
|
Term
| what are the autonomic functions of the paraventricular nucleus? |
|
Definition
| control of heart rate, blood pressure, bladder contraction, hunger |
|
|
Term
| what fibers run in the dorsal longitudinal fasciculus? |
|
Definition
| connections to reticular system and raphe nuclei of brainstem; controls arousal via reticular activating system |
|
|
Term
| what fibers travel via the perforant pathway? what is their origin and destination? |
|
Definition
| fibers from the entorhinal cortex travel via the perforant pathway to get to the dentate gyrus |
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