Hypothalmus/Thalamus/Limbic DSA

Question 1

Where is the hypothalamus found?

Answer 1

• In diencephalon, separated superiorly from dorsal thalamus by hypothalamic sulcus
• Rostral (lamina terminalis)
• Caudal (merges into tegmentum and PAG)
• Lateral (substantia innominate and medial edge of post. limb of int. capsule)
• Medial (inferior portion of 3rd ventricle)

Question 2

Preoptic area of hypothalamus

Answer 2

Transition region extending rostrally to basal forebrain

- Medial/lateral preoptic nuclei

Question 3

Role of medial preoptic nuclei?

Answer 3

Contains neurons with GnRH

Question 4

Periventricular zone of hypothalamus

Answer 4

Adjacent to 3rd ventricle

- Synthesizes RHs

Question 5

Medial zone of hypothalamus

Answer 5

Supraoptic region, tuberal region and mammillary region

Question 6

Lateral zone of hypothalamus

Answer 6

Medial forebrain bundle

• Lateral hypothalamic nucleus
• Tuberal nuclei (tuberoinfundibular tract)

Question 7

Contents of supraoptic region?

Answer 7

• Supraoptic (oxytocin) and Paraventricular (ADH) nuclei
• Suprachiasmatic nucleus (input from retina/mediates circadian rhythms)
• Anterior nucleus (visceral/somatic functions)

Question 8

Contents of tuberal region?

Answer 8

• Ventromedial nucleus (satiety center)
• Dorsomedial nucleus (emotional behavior)
• Arcuate nucleus (RHs)

Question 9

Contents of mammillary region?

Answer 9

• Medial mammillary nucleus
• Intermediate and lateral mammillary nuclei
• Posterior hypothalamic nucleus

Question 10

Blood supply for hypothalamus?

Answer 10

Anteromedial group (anterior communicating/A1)
Posteromedial group (posterior communicating/P1)

Question 11

Blood supply to tuberal region?

Answer 11

Rostral part of post. communicating a.

Question 12

Blood supply to mammillary region?

Answer 12

Caudal part of post. communicating a.

Question 13

Hypothalamic afferents?

Answer 13

• Fornix (largest single input)
• Medial forebrain bundle
• Amygdalohypothalamic fibers (stria terminalis and ventral amygdalofugal pathway)

Question 14

Ascending hypothalamic pathways?

Answer 14

• Mammillary fasciculus comes from medial mammillary nucleus and projects to ant. nucleus (in thalamus)
• Hypothalamothalmic fibers (lateral preoptic area to dorsomedial nucleus and amygdaloid nucleus

Question 15

Direct links b/w hypothalamus and ANS

Answer 15

• Hypothalamospinal (terminate on IML)

- Hypothalamomedullary (terminate @ solitary nuc., dorsal vagal motor nuc., and nuc. ambiguus)

Question 16

Indirect links b/w hypothalamus and ANS

Answer 16

• Posterior longitudinal fasciculus (to PAG)

- Mammillotegmental tract (target post./ant. tegmental nuclei)

Question 17

Pathways b/w hypothalamus and pituitary

Answer 17

• Supraopticohypophysial tract (oxytocin and ADH to post. pit.)
• Tuberoinfundibular tract (input from parvicellular neurons in arcuate nucleus and PVZ)

Question 18

Role of suprachiasmatic nucleus?

Answer 18

Mediates circadian rhythms (with input from retina)

Question 19

Principal cell groups of thalamus?

Answer 19

• Anterior
• Medial
• Lateral
• Intralaminar nuclear groups
• Midline thalamic nuclei

Question 20

Role of functional thalamic nuclei?

Answer 20

• Most project to IL cerebral cortex
• Relay general and special sensory info
• Receive inputs from cerebellum and basal ganglia

Question 21

Anterior Thalamic Nuclei (I/O)

Answer 21

Input: dense, limbic-related projections from mammillothalamic tract AND hippocampus
Output: to cingulate gyrus through ant. limb of int. cap.

Question 22

Medial Thalamic Nuclei (I/O)

Answer 22

Input: receive input from frontal lobe and substantia nigra (paralaminar subdivision)
* May play role in eye movement controls

Question 23

Lateral Thalamic Nuclei (dorsal tier) (I/O)

Answer 23

In: Sup. colliculus
Out: Visual association cortex

Question 24

Lateral Thalamic Nuclei (ventral tier) (I/O)

Answer 24

• VPL and VPM reside here

- Vent. post/inf nuc. (vestibular input and projects to postcentral gyrus)

Question 25

Lateral geniculate nucleus?

Answer 25

Visual afferents

Question 26

Medial geniculate nucleus?

Answer 26

Auditory afferents

Question 27

Vasculature to thalamus

Answer 27

• Thalamoperforating aa.

Question 28

Dejerine-Roussy Syndrome

Answer 28

-CVA to larger thalamic aa. (thalamogeniculate a.) causing intense thalamic pain

Question 29

Contents of limbic system?

Answer 29

• Subcallosal area
• Cingulate gyrus
• Parahippocampal gyrus
• Uncus
• Hippocampal formation
• Subcortical nuclei

Question 30

Hippocampal Amnesia

Answer 30

• Bilateral lesions of hippocampus
• Deficits in anterograde episodic memory (cannot form new memories)
• Normal IQ, formal reasoning, procedural and working memory

Question 31

Korsakoff’s Syndrome

Answer 31

• Progressive degeneration of mammillary bodies, hippocampal complex and dorsomedial thalamic nucleus
• Impedes retention of newly acquired memories
• Confabulation (fragmented memories combined into “new memory”)
• Thiamine deficiency (alcoholism)

Question 32

Phantosmia

Answer 32

Distortion in a smell experience or perception of smell when no odor is present

Question 33

Kluver-Bucy Syndrome

Answer 33

• Bilateral temporal lesions abolishing amygdaloid complex

- Visual agnosia, hyperorality, hypermetamorphosis, placidity, hyperphagia, hypersexuality

Question 34

Uncal Herniation

Answer 34

• Uncus and parahippocampal gyrus (possible) herniate downward over tentorium cerebelli
• IL CNIII, CL CST, Respiration/abnormal reflexes over time