The Limbic System, Amygdala, and Hippocampus

The Limbic System

• Set of deep brain structures involved in motivation, emotion, and memory.
• Determines what is rewarding.

Amygdala

• Almond-shaped structure, one on each side of the brain.
• Responds automatically to stimuli, involved in discriminating objects for survival (food, mates, rivals).
• Neurons fire selectively at survival-relevant stimuli; lesions cause inappropriate behaviors.
• Crucial for intense emotions (fear, rage), emotional awareness and expression.
• Especially attuned to social stress.
• Acts as a lookout for survival-relevant events.

Hippocampus

• Plays a special role in memory.
• Extensive damage prevents retention of new conscious memories.
• It doesn't store memories but determines which information from the cortex should be "printed" into lasting neural traces.
• Involved in retrieving memories from storage.
• Attempts to reinstate the brain state from when an event occurred during memory recall.