Layers of the Brain
The human brain has three separate layers, each corresponding to an evolutionary stage.
The oldest layer is called the reptile brain, and it controls basic self-preservative, reproductive and life sustaining functions. This is the section that houses the Fight or Flight response.
Sitting on top of the reptile brain is the limbic system, dubbed the visceral brain, because it generates all our emotions.
The most recent part of the brain to develop is the neocortex, seat of our abstract, cognitive functions; memory, intellect, language, and consciousness. Unfortunately, there is insufficient communication and coordination between the neocortex and the two older levels.
This results in a chronic dissociation between the higher and lower brains which we experience in the form of conflicting drives - unconscious and conscious, savage and civilised, lusty and loving, ritualistic and symbolic. There are times when the levels do act in harmony, as in peak experiences when body and mind unite in exhilarating moments of vitality, when our actions come effortlessly, spontaneously. With heightened internal awareness and decreased physical arousal, floating increases the vertical organisation of the brain, enhancing communication and harmony between the three separate levels. Floating can provide us with peak experiences almost at will.
The reptilian, limbic system and prefrontal cortex are discussed by Stanford University's Professor Robert Sapolsky.
The bing bang theory demonstrates with humor the limbic system and prefrontal cortex