What is the limbic system?

A complex system of nerve pathways and networks in the brain that is involved in the expression of instinct and mood, in activities of the hormonal (endocrine) system, and also in the motor systems of the body.

Brain regions involved include the amygdala, hippocampus, and hypothalamus. The activities of the body that are under the control of the limbic system include self-preservation (searching for food) and preservation of the species (reproduction), the expression of fear, rage, and pleasure. Also involved in the establishment of memory patterns.