Flashcards in Neuromed Deck (116):
What area is important for the primitive survival responses?
hypothalamus, the f F's
What area of the brain is responsible for the highest cognitivie function and control over emotion?
What area is responsible for the storage of emotional memories?
What area is responsible for remembering details of our lives?
What is LTP?
A cellular model for learning and memory; it is also known as long term potentiation
How is LTP generated?
through changes in synaptic function, operates in a network of neurons, pathway specific
What does neurogranin control?
the synaptic plasticity balance, through its regulation of CaM availability
Where is the diencephalon located?
it is between cerebral cortex and brainstem, medial to internal capsule; divided in midline by 3rd ventricle
What are the subdivisions of diencephalic portion of brain?
dorsal thalamus or thalamus
What lies within the epithalamus?
habenular nuclear complex, pineal gland and posterior commisure
What does the pineal gland do?
synthesizes serotonin and converts it to melatonin
What does habenula do?
Involved in the limbic pathway
What is located within the dorsal thalamus?
thalamic nuclei, external medullary lamina and internal medullary lamina
What does the thalamic nuclei do?
provides a strong link to cerebral cortex
What does the external medullary lamina?
A narrow band of myelinated fibers lateral to thalamic nuclei
What does the internal medullary lamina do?
A band of myelinated fibers that subdivide thalamic nuclei into different nuclear group
What is located within the ventral thalamus?
reticular nucleus of the thalamus and ventral lateral geniculate nucleus
What is within the subthalamus?
zona incerta and subthalamic nucleus
What is the subthalamus fucntion?
involved with basal ganglia and extrapyramidal activity
What is the function of the zona incerta?
rostral extension of the brain stem reticular formation
What is located within the hypothalamus?
hypophysis (pituitary gland)
hypophyseal portal system
What is the function of the hypothalamus?
Controlling center of the ANS; nerobehavioral functions and regulation of horomnes released by hypophysis
What is the hypophyseal portal system?
Vascular connection between the hypothalamus and the anterior pituitary
What is the blood supply to the diencephalon?
Mainly supplied by circle of willis;
internal carotid artery
What is the major function of the thalamus?
Gateway to the cortex
relays all sensory information to the cerebral cotex
relays information about motor activities to the cerebral cortex
integrates sensory info from different modalities
relays emotional and affective info to the cortex
Papez circuit of the limbic system
intimately involved in control of alertness, arousal and sleep
under direct cortical feedback and control; reciprocal connections between the thalamus and cortex
What are teh typical responses in sensory thalamic relay neurons?
single cell response in VPL of human during therapeutic surgery: bursts of discharge in specific relay nucleus of VPL when a specific sensory periphery on the contralateral body is stimulated
What usually causes thalamic syndrome?
usually caused by a vascular lesion or tumor; rare
usually involves damage to VPL
What is the pathology of thalamic syndrome?
painful sensations appear with noxious stimuli; then pressure, touch and vibration
in time a state of spontaneous or constant or paroxysmal pain on contralateral side
threshold for pain, temp and tactile sensation si usually raised on affected side
but once threshold is reached pain has strong emotional overtone
What are the functional characteristics of reticular activating system?
activated by repetitive, low frequency stimulation
interconnected with each other and reciprocally with specific thalamic nuclei
repetitive stimulation of the non-specific thalamic nuclei evokes cortical recruitment responses that waxes and wanes
controls the level of excitablility of neurons over wide areas of cortex
What is the afferent to the midline nuclei?
reticular formation and hypothalamus
What is the efferent from the midline nuclei?
What is the function of teh midline nuclei?
What are teh parts of the intralaminar nuclei?
What is the afferent of hte intralaminar nuclei?
reticular formation, spinothalamic tract, globus pallidus and cortical areas
What is the efferent of hte intralaminar nuclei?
Basal ganglia and wide areas of cortex
What is the function of hte intralaminar nuclei?
role in pain, sleep and wakefulness
What is the afferent of the reticular nucleus?
cortex, thalamus, Brain stem RF
What is the efferent of the reticular nucleus?
What is the function of the reticular nucleus?
modulation of thalamic activity
What is the typical response in sensory thalamic relay neurons?
single cell response in VPL of human during therapeutic surgery.
What is the cerebral cortex derived from embryologically?
What is the archicortex composed of?
hippocampus and dentate gyrus
What is the the paleocortex composd of?
oflactory cortex and parts aorund it
What is the neocortex?
The outerportion of the cortex
What is the internal structure of the cerebral cortex?
Archicortex is 3 layers and most of the rest of the cotex (neocortex) is 6 layers
What are the 6 layers of the neocortex?
molecular layer, external granular layer, external pyradmial layer, internal granular layer, internal pyramidal layer, multiform layer
What is the role of the suprachiasmatic nucleus?
regulates circadian rythm
lesions cause insomnia
neurons lost in alzheimers and shift work
What is the role ofthe anterior nucleus of the hypothalamus?
lesion casues hyperthermia
endogenou pyrogens cause fever
What is the role of the medial hypothalamus?
regulates feeding behavior
lesion causes overeating
loss seen in prader-willi syndrome
DHF originates mostly from where and travels where?
paraventricular nucleus and travels laterall in brainstem
What 3 neurons are involved in sympathetics to the eye?
DHF T1 to T2; preganglionic fiber from interomediolateral cell column to SCG; SCG to pupillary dilator muscle
What is hirschprung's disease?
congenital absence of myenteric plexus
results in no peristalsis in denervated colon
A spinal cord lesionin thoracic cord of sympathetic nerve causes what defiing symptom?
What is the result of a pancoast tumor?
result of a direct spread of tumor usually lung onto sympathetic chain; spinal cord lesion
What is anisocoria?
What is a way to differentiate between sympathetic and parasympathetic causes?
examining pupils in light and dark and associated symptoms
What would occur with the eye ina left sympathetic lesion?
failure of the left eye to dialate
How can the ICA cause horners syndrome?
a carotid dissection and expasion of artery can stretch sympathetics can cause horner's
how does one test paraympathetics to the eye?
shine flash light to test; swinging flashlight should result in direct and consensual constriction
Incontinence could be due to what?
Chemotherapy for prostate cancer. hyperactive bladder(spastic)- upper sympathetic lesion
underactive bladder-sympathetic lower lesion
hypoactive bladder (flaccid)
overactive sphincter-lesion of parasympathetic
What is a dysfunction of the cerebral cortex usually caused by?
hemmorhage, thrombosis or tumor
What is a tumor of the cerebral cortex usually originated from?
glial cells also called pretty cells
Which hypothalamic nucleus is responsible for making you fat?
Lateral Hypothalamic Area
What is POMC/CART?
You don't want to eat anymore supposedly
What is the tuber cinereum?
a gray protuberance, a bulge located between optic chiasm and mammillary bodies
What are the mamillary bodies functionally apart of?
the limbic system
Why is the hypothalamus so vascularized?
key component of the responsiveness of hte specific hypothalamic neuronal populations ot the negative feedback actions of circulating horomones
The hypothalamus is divided into what zones?
periventricular, medial and lateral areas
What is the role of hte lateral zone of the hypothalamus?
region comprised of loosely arranged neuronal cell groups and importantly is traversed by fibers of medial forebrain
What are the three major regions of the lateral zone of the hypothalamus?
lateral preoptic nucleu
lateral hypothalamic area
What is the role of the lateral hypothalamic area?
induces eating when stimulated; ablation causes anorexia and starvation. Cotains neurotransmitters that increase food intake
What is the role of tuberomammillary nucleus?
located at ventrolateral surface at tuberal and mammillary levels of the medial zone. Region contains large neurons that release histamine as a neurotransmitter
actively inhibited during sleep
What is the role of the medial zone of the hypothalamus?
divided into four anatomically distinc regions involved in different things
What is the role of the preoptic region of the medial zone?
anterior region contains neurons that regulate gonadotropin secretion from adenohypophysis. Developmentally regulated by testosterone
What is the role of anterior region-suprachiasmatic nucleus?
compact nucleus plays role in circadian rythm and receives input directly from retina
What is the role of the anterior hypothalamic nucleus?
region lies between suprachiasmatic and paraventricular nuclei involved in temperature regulation
What does a lesion of hte anterior hypothalamic nucleus cause?
What is the role of the paraventricular nucleus?
releases neuropeptides that regulate a variety of key functions
What is the role of the supraoptic nucleus?
contains neurons that syntehsize AVP and oxytocin
What is the dorsomedial nucleus?
involved in blood pressure regulation; stimulations results in aggression
What is the role of the ventromedial nucleus?
nucleus inhibits urge to eat when stimulated; relay ingestion-related signals to brainstem
What is the role of the arcuate nucleus?
located ventrally in tuber cinereum and via projections to median eminence and portal vasculature; controls release of various adenohypophyseal horomones
important in feeding behavior
What is the role of the posterior nucleus?
neurons in this area are involved in thermoregulation
What does lesion of hte posterior nucleus result in?
inability to thermoregulat, termed pokilothermia
What is the role of mamillar nucleus?
actually a seriesof nuclei, part of limbic system
What is does damage to mamillary nucleus result in?
associated wtih memory disturbance due to extensive interconnectivity with hippocampus
What is the role of the periventricular zone?
layer of cells lining third ventricle at supraoptic and tuberal levels
consists of several small nuclei that are often considered a part of the medial zone
What are the major fiber tracts of the hypothalamus?
medial forebrain bundle
What is the role of the fornix?
mammillary bodies of hypothalamus receive a large axonal projection form hippocampus via this pathway
What is the role of the mammilothalamic tract?
projects form mammillary body to the anterior nucleus of hte thalamus
What is teh role of the stria terminalis?
prominent pathway interconnecting the amygdaloid complex with the medial zone of the hypothalamus
What is the role of the medial forebrain bundle?
Most complex fiber pathway in the CNS containing at least 50 distinct constituent parts or pathways; throughout entire lateral hypothalamic zone
What is supraopticohypophyseal tract?
conducts fibers from the supraoptic and paraventricular nuclei to neurhypophysis; axons of large neurons that syntehsize either AVP or oxytocin
What is the role of tuberoinfundibular tract?
conducts fibers from the arcuate nucleus to the hypophyseal portal system at the median eminence of the infundibulum. Axons carry neuropeptide releasing or inhibitn factors which act upon anterior pituitary cells.
What is the role of the hypothalamospinal tract?
contains descending axons that regulate spinal cord preganglionic neurons of both sympathetic and parasympathetic division of the autotomic nuervous system.
What are the major regulatory functions of hte hypothalamus?
feeding and energy, emergency reponses to stress, blood pressure and electrolyte composition,
How is the anterior hypothalamic nucleus involved in thermoregulation?
contains neruons that are sensitive to warmth and trigger heat dissipation through multiple mechanisms by activating portions of parasympathetic nervous system
What is the role of the posterior hypothalamic nucleus?
contains neurons that are sensitive to cold, triggering heat conservation and active heat generation metabolism
What two regions are involved in feeding and satiety respectively?
lateral hypothalamic area and ventromedial hypothalamic nucleus
What is the role of arcuate nucleus in feeding?
neurons play a central role in regulation of feeding
What are the two sets of neurons within the arcuate nucleus involved in eating?
POMC/CART neurons that coexpress POMC and melanocyte stimulating horomne and neurons that coexpress AgRP and neuropeptide Y
What is craniopharyngioma?
congenital tumor originating from remnants of Rathke's pouch
common supratentorial tumor
pressure on optic chiasm resutls in bitemporal hemianopsia
pressure on overlying hypothalmus results in hypothalamic syndrome
What is hypothalamic memory disturbance?
posterior hypothalamic lesions involving mammillary bodies
associated with inability to form new memories for context and time specific events
What is klein-levin syndrome?
hypothalamic disorder pirmary in adolescent males
episodic compulsive eating
associated with decrease in dopaminergic tone
What is the dorsal root ganglion characterized by?
tight packing of neuron cell bodies
What are the difference between characteristics of sympathetic and sensory ganglion?
sympathetic has smaller neuronal cell bodies and looser packed soma with fewer sattelite cells
The cell bodies of neurons within the sympathetic ganglion belong to what sympathetic neuron?
The cell bodies of preganglionic sympathetic neurons are located where?
interomediolateral cell colum of spinal column
The intermediolateral cell column is present in what spinal cord levels?
The neuron cell bodies located in the lateral horn are what?
Axons of neurons in lateral horn reach sympathathetic chain via what structures?
white communicating rami
At what level of the brainstem would you expect to find the edinger westphal nucleus?
The parasympathetic fibers from Edinger-Westphal nucleus synapse onto what postganglionic neurons in which ganglion?
What is target organs innervated b neurons on Edinger-westphal nucleus?
sphincter pupillae muscle
What is anisocoria?
a condition in which pupils are different size