Hypothalamus & Limbic

Question 1

What is the main function of the hypothalamus?

Answer 1

Maintains homeostasis (feeding, thirst, salt, thermoregulation, sleep, sickness) and special survival drives (sexual behavior, parenting, social, curiosity, aggression)

Question 2

What is the function of the arcuate nucleus of the hypothalamus?

Answer 2

Release hormones for anterior pituitary. Affected by stress.

Question 3

What is the function of the suprachiasmatic nucleus?

Answer 3

Biological clocks: circadian and circannual

Question 4

What is the function of the paraventricular nucleus?

Answer 4

Anterior & posterior pituitary hormones

Autonomics

Question 5

What is the function of the mammillary nucleus?

Answer 5

Memory (from hippocampus via fornix)
Spatial memory/position of head in space
To brainstem reticular formation and anterior thalamic nuclei

Question 6

What is the Papez circuit?

Answer 6

The limbic circuit between the hypothalamus, cortex, hippocampus and amygdala

Question 7

Is the pathway of the Papez circuit?

Answer 7

Hippocampus through fornix to mamillary body, through mammilothalamic tract to anterior nucleus of thalamus, to cingulate gyrus, back to hippocampus.
There are also hippocampal projections to the amygdala, which go the the hypothalamus and then to the association cortex before returning to the hippocampus.

Question 8

Which part of the pituitary is involved with direct activation and which is involved with indirect activation?

Answer 8

Direct: posterior pituitary = neurohypophysis
Indirect: anterior pituitary = adenohypophysis

Question 9

List the nuclei of the amygdala and their primary function

Answer 9

Medial: olfactory system
Central: emotional responses
Basolateral: Link experience of emotions and their expression

Question 10

What are the major inputs to the amygdala?

Answer 10

Sensory input: sights, sounds, touches, smells, tastes
Olfaction to the medial, the rest to the basolateral
Visceral sensory inputs reach the central nuclei

Question 11

What are the fiber tracts leaving the amygdala?

Answer 11

Stria terminalis and ventral amygdalofugal pathway

Question 12

What is the overall function of the amygdala?

Answer 12

Important role in analyzing whether a remembered event is good or bad, and triggering the appropriate response
Crucial for conditioned responses, fear response

Question 13

What is Kluver-Bucy syndrome?

Answer 13

Bilateral lesions to the tips of the temporal lobes causes Docility, Hyperphagia, Hyperorality, Hypersexuality and visual agnosia

Question 14

How many layers make up the hippocampus?

Answer 14

3 layers: CA1, 2 and 3

Question 15

Where do inputs to the hippocampus originate?

Answer 15

Cortex via the entorhinal cortex
Septal nuclei via the fornix
Amygdala

Question 16

Where do the outputs from the hippocampus go to?

Answer 16

Cortex via the entorhinal cortex

Mamillary bodies via the fornix (to limbic cortex)

Question 17

What form of memory is lost in Alzheimer’s disease?

Answer 17

Declarative memories. Patients cannot form new memories (anterograde amnesia). Nondeclarative memories (skills/procedures) are unaffected.

Question 18

What is Wernicke-Korsakoff syndrome?

Answer 18

Thiamine deficiency often associated with alcoholism

Wernicke’s encephalopathy (acute phase) and Korsakoff’s amnesic syndrome (chronic phase)

Question 19

What is hippocampal sclerosis?

Answer 19

Severe neuronal cell loss and gliosis of the CA1 region and subiculum of the hippocampus. Similar presentation to Alzheimer’s.

Question 20

What are the functions of the septal nuclei?

Answer 20

Regulates gonadal hormone secretion, reproductive and sexual behaviors
Facilitates memory formation

Question 21

Lesions of the septal nuclei cause what?

Answer 21

Septal rage: behavioral overreaction

Question 22

What is Pick’s disease?

Answer 22

Frontotemporal dementia causing progressive destruction of neurons
Buildup of tau proteins in neurons (Pick bodies)