Forebrain and Limbic System Flashcards
divisions of forebrain
- diencephalon
- internal capsule
- limbic system
divisions of diencephalon
- epithalamus: pineal gland, habenula
- thalamus: all sensory (minus olfaction) paths relay here, composed of distinct nuclei
- hypothalamus
- subthalamus
divisions of limbic system
- hippocampus
- hypothalamus
- amygdala
subdivisions of thalamic nuclei (as defined by internal medullary lamina)
- ant: ant nucleus, important limbic relay, sits in split in IML
- med: dorsomedial
- lat: 1. dorsal tier- lateral dorsal, lat post, pulvinar 2. ventral tier- vent ant, VPL, VPM, med and lat geniulates
* largest subdivision* - intralaminar: centromedian, parafascicular
- reticular nuc: regulatory role
- midline nuc
theme of all thalamic nuclei (except reticular)
- projection neurons: provide output from thalamus
- interneurons: small, inhibitory
*proportions vary
3 categories of thalamic nuclei
- relay nuc: receive well defined specific input from subcortical source and project to well defined area of cortex
- association nuc: receive specific inputs and regulatory from association cortex and project abck
- intralaminar and midline nuc: receive distinct set of specific inputs, project to cortex, BG, and limbic structures
reticular nucleus
- imp source of regulatory input to thalamus
- no projections to cortex
- input: cortex and thalamus
- output: inhib axons to thalamus
sensory system relay nuclei
VPL and VPM
motor system relay nuc
VA and VL
limbic system relay nuc
anterior, LD
main association nuc
DM (prefrontal lobe)
pulvinar (parietal-occipital-temporal)
internal capsule
- thalamocortical and corticothalamic fibers pass thru
- collects and forms cerebral peduncle (corticopontine/bulbar/spinal fibers descend thru)
5 parts of internal capsule (based on relationship to lenticular nucleus)
- ant limb: lenticular nuc, caudate
- post limb: lenticular nuc, thalamus
- genu: btwn A and P limbs
- retrolenticular: behind lenticular nuc (inf visual field)
- sublenticular: not seen in horiz sections, sup visual field
hypothalamus
critical in autonomic, endocrine, emotional, and somatic fnctns, maintains homeostasis
3 types of hypothalamus connections
- interconnected w limbic system
- output to pituitary
- interconnects visceral/somatic nuc
hypothalamic control of pituitary
sup hypophyseal br: cap bed in infundibulum and 2nd cap bed around endocrine cells, caps drain into portal vessels in ant lobe
inf hypophysela br: neurohypophysis , caps drain into cavernous sinus, delivers ant and post pit hormones to systemic circ
what controls pituitary secretions
neuroendocrine cells