EEG and MEG        Methods of Monitoring the Brain         The
brain is the control center of the human body.  It sends and
receives millions of signals every second, day and night, in the
form of hormones, nerve impulses, and chemical messengers.  This
exchange of information make us move, eat, sleep and think. 
 Obstructions such as tumors can interrupt normal brain
activity, leading to deficits of normal reasoning, motor
control, or consciousness. Many of the signs of neural damage
are easily recognizable by an outside observer, but since the
actual cause of these problems are internal, the symptoms can be
vague.  The real deficits can affect the brain's anatomy, or the
way signals are processed.  A physician can only determine the
real cause by examining the brain internally to find
irregularities, either in structure or in functioning.  Since
the brain is extremely fragile and difficult to access without
risking further damage, imaging techniques are used frequently
as a noninvasive method of visu