DSA-Hypothalamic And Limbic Systems

Question 1

Hypothalamus Function

Answer 1

Maintenance of homeostasis

Question 2

Hypothalamus Location

Answer 2

Just posterior to optic chiasm, posterior merges into tegmentum and PAG, forms floor and ventral walls of 3rd ventricle

Question 3

Mammillary Bodies

Answer 3

Posterior part of hypothalamus

Question 4

Tuber Cinereum

Answer 4

Small swellings b/t mammillary bodies and optic tracts

Question 5

Median eminence

Answer 5

Arises from tuber cinereum and narrows into infundibulum

Question 6

Nuclei of Medial Zone of HT: Supraoptic Region

Answer 6

Supraoptic/paraventricular nucleus:
-contain oxytocin and ADH
—lesion results in diabetes insipidus (=increase H20 and urination)

Suprachiasmatic Nucelus
-retinal input; involved in circadian rhythms

Anterior Nucelus
-range of visceral/somatic fxns

Question 7

Nuclei of Medial HT: mammillary region

Answer 7

Medial mammillary nucleus
-afferents from hippocampus via fornix
-efferent to thalamus and Brainstem
—lesions=inability to turn short term memory into long term

Question 8

Tuberal Region of Hypothalamus

Answer 8

Ventromedial nucleus
-satiety venter
—lesions result in excessive eating

Dorsomedial Nucelus
-emotional behavior; stimulation causes sham rage
—destruction results in decreased aggression

Question 9

Blood Supply to HT

Answer 9

Anteromedial group
-anterior comm and ACA

Posteromedial Group
-Posterior comm and PCA
—rostral part of PComm=tuberal, caudal part of PComm=mammillary

Question 10

Afferents to HT

Answer 10

Fornix
-from subiculum and hippocampus
—largest single input to HT

Medial Forbrain bundle
-interconnects septal nuclei, HT and Midbrain

Amygalohypothalamic Fibers
-stria terminalis and Ventral amygdala fugal pathways

Question 11

Efferent from HT

Answer 11

Mammillary Fasciculus
-originates from medial mammillary nucleus
—splits into mammillothalamic and mammilotegmental tracts
—important part of circuit of Papez

Hypothalamothalamic Fibers
-from lateral prep-tic area to dorsomedial thalamus and amygdala

Question 12

HT Direct link to ANS

Answer 12

Hypothalamomedullary Fibers
-to solitary nuc, dorsal Vargas motor nuc and nucleus Ambiguus

Hypothalamospinal fibers
-intermediolateral cell column
—lesions to anterolateral medulla disrupts (Horners)

Question 13

Indirect Link of HT to ANS

Answer 13

Posterior Longitudinal Fasciculus and Mammillotegmental Tract
-target PAG, which will then go to other areas of Brainstem

Question 14

Supraopticohypophysial Tract

Answer 14

Made of axons of neurons in SON and PVN

-produce Oxytocin and ADH, which is stored in Herring bodies

Question 15

Tuberoinfundibular Tract of HT

Answer 15

Input from neurons in Periventricular zone, convey releasing hormones to median eminence and infundibulum

Question 16

Hippocampal Formation Afferent Pathway

Answer 16

Dentate Nucleus to CA3–>CA1–>subiculum

Question 17

Hippocampal Formation Efferent Pathway

Answer 17

Subiculus—>fornix

-projects to medial mammillary nuc, ventromedial nuc and anterior nucleus

Question 18

Amygdala afferent pathway

Answer 18

From Interior temporal association cortex, thalamus, and brainstem

Question 19

Amygdala Efferent pathways

Answer 19

Stria Terminalis
-output to hypothalamus and basal ganglia for motor responses

Ventral Amygdalofugal Pathway
-many areas of the brain

Question 20

Papez Circyuit

Answer 20

Cingulate Gyrus—>hippocampus

Hippocampus—> Fornix—>medial mammillary Nuclei

Medial Mammillary Nucleus—>anterior nucleus

Anterior Nucelus—>cingulate gyrus

Question 21

Septal Region of Limbic Structures

Answer 21

Rostral to anterior commissure and control of rage behavior

Question 22

Nucleus Accumbens of Limbic Structures

Answer 22

Plays important role in addiction and chronic pain

Efferents to HT, brainstem, and globus pallidus

Question 23

VTA of Limbic System

Answer 23

Medial to substantia nigra
-connections w ventral striatum

Efferents to Nucleus Accumbens and plays role in reward and motivation

Question 24

Hippocampal Amnesia

Answer 24

Bilateral lesion of hippocampi

-cannot learn new material (anterograde episodic memory) and spared procedural and working memory

Question 25

Korsakoff’s Syndrome

Answer 25

Thiamine Def; associated with chronic alcohol use -impedes retention of newly acquired memory through degradation of mammillary bodies, hippocampus and dorsomedial nucleus Difficulty understanding written material and meaningful convos

Question 26

Anosmia

Answer 26

Loss of smell through viral infection, obstruction, or congenital defect

Question 27

Phantosmia

Answer 27

Distortion in a smell experience or perception of smell when not present -lesion of anterior/medial temporal lobe

Question 28

Kluver-Bucy Syndrome

Answer 28

Bilateral temporal lobe lesions that abolish amygdala - Visual agnosia - hyperorality (examine objects by mouth) - hypermetamorphosis (overreact to visual stim) - placidity (may not show fear when they should) - Hyperphagia - hypersexuality

Question 29

Uncal herniation

Answer 29

Uncut and parahippocampal gyrus over edge of tentorium cerebelli -CN III, CST, and CBT all affected