The Reptilian Brain has the most primitive structures of the human brain, is sometimes called the lizard brain, and is 250-300 million years old. It is our oldest brain, purely physical, and basically sits on top the spinal cord. The Reptilian Brain is sub-limbic: i. e. it is positioned below mammalian neuronal structures. It involves neuronal structures on the brain stem: i. e. medulla, pons, some old basil nuclei, and the mesencephalon. It has the cerebrum that is involved with movement. The Reptilian Brain doesn’t know the difference between what is real and what is not real and it is non-emotional. It is rigid and obsessive-compulsive. It is pre-social, and as such doesn’t have a social component. That is, in the need for survival the Reptilian Brain became non-social and instinctively reactive and aggressive. The key functions of the Reptilian Brian are: 1.) receives stimuli – it is the first responder defending against incoming stimuli. The Reptilian Brain has an instinctive spontaneous reaction to imminent danger to insure survival. It acts/re-acts at a pure instinctual level. The human basal need for safety/survival is most likely connected to this early Reptilian survival “fight-flight” reaction. In the Theory of Balanceology, I indicate how safety/survival is a basal key human motivational need —> actually a need for all living things, and 2.) regulates basic life processes – the Reptilian Brain is involved in regulation of reflexes, heart rate, respiration, metabolism, breathing, and sleeping. It includes functioning to regulate blinking, physical balance, and bodily movement.