"The primary task of the brain is to help maintain the whole body in an
optimal state relative to the environment, in order to maximize the chances
of survival. The brain does this by registering stimuli and then responding
by generating actions. In the process, it also generates subjective
experience" (Carter, 2009, p. 38).
Sources of brain stimuli: sensations, perceptions, emotions (Carter,
2009, p. 39 "Thoughts").
"The signals that travel along the spinal chord are known as nerve
impulses" (Cater, 2009, p.42).