The prefrontal cortex an integral link between a person's personality and the functions of the prefrontal cortex. This brain region has been implicated in planning complex cognitive behavior, personality expression, decision making, and moderating social behavior. The basic activity of this brain region is considered to be orchestration of thoughts and actions in accordance with internal goals.
The Hippocampus plays important roles in the consolidation of information from short-term memory to long-term memory and spatial navigation.
The Amygdala Shown to play a key role in the processsing of emotions and to perceive them in other people. This includes fear and the many changes that it causes in the body, like crushing teeth and making fists when angry and cryign when sad.