The brain controls both conscious behavior (e.g., walking and thinking) and most involuntary behavior (e.g., heartbeat and breathing). In higher animals, it is also the site of emotions, memory, self-awareness, and thought. It functions by receiving information via nerve cells (neurons) from every part of the body, evaluating the data, and then sending directives to muscles and glands or simply storing the information. Information, in the form of electrochemical signals, moves through complex brain circuits, which the networks of the billions of nerve cells in the nervous system.