A complex system of nerves and networks in the brain, involving several areas near the edge of the cortex concerned with instinct and mood. It controls the basic emotions (fear, pleasure, anger) and drives (hunger, sex, dominance, care of offspring).
Your amygdalae are essential to your ability to feel certain emotions and to perceive them in other people. This includes fear and the many changes that it causes in the body. If you are being followed at night by a suspect-looking individual and your heart is pounding, chances are that your amygdalae are very active.
The hippocampus is involved in the storage of long-term memory, which includes all past knowledge and experiences. Scientists are unsure exactly how this occurs. In particular, the hippocampus seems to play a major role in declarative memory, the type of memory involving things that can be purposely recalled, such as facts or events.
The hypothalamus is a section of the brain responsible for the production of many of the body’s essential hormones, chemical substances that help control different cells and organs. The hormones from the hypothalamus govern physiologic functions such as temperature regulation, thirst, hunger, sleep, mood, sex drive, and the release of other hormones within the body. This area of the brain houses the pituitary gland and other glands in the body.
Reticular activating system the system of cells of the reticular formation of the medulla oblongata that receive collaterals from the ascending sensory pathways and project to higher centers; they control the overall degree of central nervous system activity, including wakefulness, attentiveness, and sleep;