The death of each day's life, sore labour's bath, Balm of hurt minds, great nature's second course, Chief nourisher in life's feast. To keep ourselves physically fit and mentally stable, we engage in various forms of self-regulation, such as exercise, relaxation, and meditation. In the course of a day, we go from waking to sleeping.
Neurotransmitters are chemicals that neurons use to signal and stimulate one another.
When we are awake, the first two of these transmitters contribute to our alertness and responsiveness to the outer world. But throughout the day, these chemicals are gradually depleted. As we traverse states of mind all the way to dreaming, they are at their lowest ebb. Then the third neurotransmitter, acetylcholine, takes over as brain-stem neurons stimulate a flurry of activity in the higher cortical areas of the brain. Hobson compares this activity to a seizure.