2. LIMBIC SYSTEM

3. History Paul Broca (1824-1880): 1878: “le grand lobe limbique”
Refers to a ring of gray matter on the medial aspect of the cerebral hemispheres.
James Papez ( ):
1930’s: defined a limbic system that might underlie the relationship between emotion and memory (Papez’ circuit).

4. Components Amygdaloid body Hippocampus (“seahorse”) Cingulate gyus
Parahippocampal gyrus
Hypothalamus
Mamillary bodies
Anterior nucleus of thalamus

6. Functions Associated with memory Associated with pain/pleasure, rage
“Emotional brain
Emotional and motivational aspects of behavior.
Provides emotional component to learning process:
Especially the amygdala.
Associated with memory
Especially the hippocampus.
Associated with pain/pleasure, rage

7. Amygdala Large nuclear group in temporal lobe. Afferents:
Olfactory tract
Solitary nucleus
Parabrachial nucleus
Limbic neocortex:
Cingulate gyrus
Parahippocampal gyrus

8. Regions of the Amygdala
Large basolateral region:
Provides direct input to basal ganglia and motor system.
Small corticomedial group of nuclei:
Related to olfactory cortex.
Medial and central nuclei:
Connected to hypothalamus.

9. Functions of the Amygdala
Relate environmental stimuli to coordinated behavioral autonomic and endocrine responses seen in species-preservation.
Responses include:
Feeding and drinking
Agnostic (fighting) behavior
Mating and maternal care
Responses to physical or emotional stresses.

10. Pathologies (lesions)
Voracious appetite
Increased (perverse) sexual activity
Docility:
Loss of normal fear/anger response
Memory loss:
Damage to hippocampus portion:
Cells undergoing calcium-induced changes associated with memory

11. Kluver-Bucy Syndrome:
Results from bilateral destruction of amygdala.
Characteristics:
Increase in sexual activity.
Compulsive tendency to place objects in mouth.
Decreased emotionality.
Changes in eating behavior.
Visual agnosia.