The human brain has evolved over millions of years, each of the three layers that comprise the organ developed over time as higher functioning was required for survival. The three layers are described below.
The first layer to develop was the brain stem or ‘reptile’ brain. The brain stem is located at the base of the brain, caps the spinal chord and helps control basic attention, arousal, and consciousness. It is more combative than co-operative.
The second layer of the brain to develop is the limbic system or ‘animal brain’. This regulates the ‘flight or fight’ neurochemicals, basic decision making and sexual arousal. It stores memories that trigger strong emotions but can cloud and distort perceptions of ordinary experiences. This layer’s development allowed animals to read each other and is dedicated survival in a . Within the mesolimbic pathway is the Ventral Tegmental Area (VTA). The VTA projects to the Nucleus Accumbens (thought to be the reward center). The neurotransmitter most commonly linked with the mesolimbic system is dopamine. This is where addiction ‘lives’.
The final layer to develop is the Cerebral Cortex or ‘higher brain’. This largest, wrinkled, outer layer of the brain is responsible for attention, perception, awareness, conscious thought, and language. It is associated with organizing, problem solving, attention, planning, decision making and a number of more complex cognitive functions including behavior and emotion. The functions that make up the personality are initiated here. In short, the frontal lobe is the portion of the brain that makes us who we are.
