The Limbic System

Question 1

Describe the anatomy of the olfactory

Answer 1

Olfactory bulb is sitting in the cribiform plate, the axons of the bipolar cells pass through the cribriform plate and up through the skull. Bipolar cells synapse at glomerulus with second order olfactory neurones which send signals via olfactory tract. The second order olfactory neurones are called olfactory bulb mitral cell > split to form two olfactory stria. The higher processing of the smell goes on the piriform and orbitofrontal cortices

Question 2

Explain what the limbic system is

Answer 2

System responsible for processes aimed at survival of the individual: maintenance of homeostasis via activation of visceral effector mechanisms, modulation of pituitary hormone release and initiation of feeding and drinking > agonistic behaviour

Question 3

Explain what the paper circuit is and the DTI

Answer 3

The paper circuit: neural circuit for the control of emotional expression, its the mammillary in hypothalamus damaged in chronic alcoholism

DTI: type of imaging shows co-instant activity in different parts of the brain > hence can show parts of the brain working together.

Question 4

Describe the structure and function of the hippocampus

Answer 4

1. Afferent pathway: preforant pathway - the main connections are from the adjacent cortex (emotional cortex) through the prefrontal pathway and the adjacent piece of cortex (from everywhere else)
2. Efferent - fornix (output pathway)

Functions: memory and learning.

Alzheimer’s shrinkage of hippocampus. Early: memory loss, moderate: parietal lobe and depressing apraxia, late: frontal lobe and loss of executive skills amd personality change.

Question 5

Describe the role of the amygdala

Answer 5

Fear and anxiety centre

Kluver - bucy syndrome: hyperorality, loss of fear and visual agnosia and hyper sexuality