Amygdala

Amygdala, deep in the center of the brain’s limbic system, the almond-shaped amygdala safeguards what’s necessary for basic survival, including sex and emotional reactions (anger, pleasure, fear). It helps attach emotional meaning to memories. Specifically, the amygdala is command central in the fight-or-flight response (FFR). Harm to the amygdala can affect our fear conditioning, motivation, memory, learning, and emotional regulation—leading  to aversive signals, like sweaty palms and mental conditions, like depression. The amygdala is larger in male brains, often enlarged in the brains of sociopaths, and shrinks in the elderly.