brainstem is the "stem-like" region at the base of the brain
that merges into the spinal cord. It contains the midbrain,
pons and medulla, which in turn contain groups of neurons
that are important for a variety of functions including arousal,
sleep, respiration, reflex movements, pain regulation, and
some sensory and motor functions.
by Catherine E. Myers. Copyright © 2006 Memory Loss and the Brain
Artwork copyright © 2000 Ann L. Myers