Limbic System

Question 1

What is the amygdala?

Answer 1

The amygdala is a collection of about a dozen nuclei lying beneath the uncus of the limbic lobe, at the anterior end of the hippocampus and the inferior horn of the lateral ventricle, and is very closely associated with the uncus and the parahippocampal gyrus. The nuclei are subdivided into a medial, central, and basolateral group.

Question 2

What are the medial nuclei of the amygdala connected to?

Answer 2

The medial nuclei are interconnected with the olfactory system, and are relatively small in humans.

Question 3

What are the central nuclei of the amygdala connected to?

Answer 3

The central nuclei are also small, but their interconnections with the hypothalamus and related brainstem nuclei (e.g., periaqueductal gray) are important in emotional responses.

Visceral inputs go here.

Question 4

What are the basolateral nuclei of the amygdala connected to?

Answer 4

The basolateral nuclei, the largest part of the human amygdala, are in some ways like a cortex without layers; they contain pyramidal neurons, are continuous with parahippocampal cortex, and are extensively interconnected with other cortical areas.

Question 5

What is the cause of Kluver-Bucy Syndrome?

Answer 5

Bilateral lesions to the tips of the temporal lobes, originally done to relieve intractable seizures, resulted in the following constellation of deficits due to hitting the amygdala.

Question 6

What are some of the symptoms of Kluver-Bucy Syndrome?

Answer 6

Docility
Hyperphagia
Hyperorality
Hypersexuality
Visual Agnosia

Question 7

What nucleus in the thalamus do afferent fibers from the amygdala end up in?

Answer 7

Dorsomedial Nucleus

Question 8

What does the fornix of the hippocampus end as?

Answer 8

Mamillary Bodies

Question 9

What makes up the hippocampus?

Answer 9

Dentate Gyrus and Hippocampus Proper

Question 10

What is the major interface between the hippocampus and vast areas of association cortex?

Answer 10

The anterior part of the parahippocampal gyrus

Question 11

What is the hippocampus involved in?

Answer 11

It is a key link in declarative memory.

Question 12

What is the hippocampus highly sensitive to?

Answer 12

Oxygen deprivation

Question 13

What does bilateral damage to the hippocampus often cause?

Answer 13

Anterograde Amnesia

Question 14

What are lesions in the hippocampus associated with?

Answer 14

Alzheimer’s Disease

Question 15

What is Wernicke-Korsakoff disease and what is it often caused by?

Answer 15

It is a disease of brain degeneration and it is often caused by alcohol abuse.

Question 16

What are the two phases of the Wernicke-Korsakoff disease?

Answer 16

Wernicke’s encephalopathy represents the “acute” phase of the disorder; Korsakoff’s Amnesic Syndrome represents the “chronic” phase (memory disorder, confabulation).