diencephalon

Question 1

location and components of diencephalon

Answer 1

between cerebral cortex and brainstem
surrounds the 3rd ventricle
relay info to cortex, regulate autonomic NS

components of diencephalon: Thalamus (head), hypothalamus (beak), epithalamus(ear), subthalamus (neck)

Question 2

epithalamus

Answer 2

upon the thalamus, contains the pineal gland- secretes melatonin under control of hypothalamus (biggest part of epithalamus)
posterior commisure- bottom part of the epithalamus,
habenula on top

Pineal gland: calcium deposits in pineal gland, pineal tumors often compress the midbrain

Question 3

subthalamus

Answer 3

subthalamic nucleus (of luys)-functionally part of the basal nuclei (part of indirect pathway)

zona incerta

Question 4

hypothalamus

Answer 4

below the thalamus: functions: control of ANS, body temp, hunger and thirst, sleep wake, endocrine functions, memory formation, sex drive and motivation

its a group of nuclei

related structures: mammilary bodies, infundibulum (pituitary stalk), pituitary gland (hypophysis)

hypophyseal portal system- system of blood vessels connecting hypothalamus to anterior pituitary

Question 5

thalamus

Answer 5

relays info to the cerebral cortex, group of 12 nuclei, lateral walls of third ventricle, connected by interthalamic adhesion

functions: gatekeeper of the cortex, process sensory information, send motor info from cerebellum and basal nuclei to cortex, limbic system, selective attention, alertness, arousal, sleep, feedback loop from cortex to thalamus

general thalamic circuitry:
specific inputs: fibers carrying information about a particular modality to the thalamus, regulatory inputs: feedback info from cortex where specific inputs project, projection neuron: carry info from thalamus to cortex, interneuron GABAergic inhibitory neuron within thalamic nuclei

Question 6

thalamic nuclei

Answer 6

internal medullary lamina- Y shaped white matter tract, divides thalamus into anterior, medial lateral divisions of nuclei, contains intralaminar nuclei

external medullary lamina- white matter separating reticular nucleus from rest of thalamus

anterior division- most anterior portion of thalamus

anterior nucleus- only nucleus in anterior division, input from mammillary bodies, output to cingulate gyrus (limbic)

lateral nuclear division: group of nuclei lateral to internal medullary lamina dorsal tier (LD, LP, pulvinar), ventral tier (VA, VL, VPL, VPM, LGN MGN)

Question 7

Lateral division dorsal tier

Answer 7

Lateral dorsal (LD)- input from hippocampus, out to cingulate gyrus

Lateral posterior (LP)- input from and output to parietal lobe

Pulvinar- input from and output to parietal-occipital-temporal (POT) cortex

Question 8

lateral division- ventral tier (motor)

Answer 8

Ventral anterior (VA)- input from basal nuclei, projects to premotor cortex
Ventral lateral (VL)- input from cerebellum and basal nuclei, projects to premotor and motor cortex

Question 9

lateral division- ventral tier (somatosensory)

Answer 9

ventral posterolateral (VPL): input from DCML and spinothalamic tracts, project postcentral gyrus

Ventral posteromedial (VPM): trigeminal system and gustatory inputs, projects to postcentral gyrus and insula

Question 10

lateral division- ventral tier (special sensory)

Answer 10

medial geniculate nucleus (MGN)- input from inferior colliculus, project to primary auditory cortex

lateral geniculate nucleus (LGN)- input from optic tracts, project to primary visual cortex

Question 11

medial division

Answer 11

medial division- potion medial to internal medullary lamina

medial dorsal nucleus (MD)- input from cortex, amygdala, olfactory structures, projects to prefrontal cortex

Question 12

diffuse projection nuclei

Answer 12

Diffuse projection nuclei- project to wide cortical areas

Intralaminar nuclei- embedded within internal medullary lamina
Midline nuclei- fuse at interthalamic adhesion
Reticular nucleus- relays with other thalamic nuclei