QUESTION:
What kind of an effect does the moon's gravitational pull have on the human
brain. There are many myths and legends that talk about the full moon's
effect on human behavior.  Does this have anything to do with the moon's
effect on
fluids (i.e., brain fluid) as it does on oceans and tidal action?

ANSWER from Wally Welker on December 16, 1997:
The myths about the moon's effects on human brain are just myths.  Most
myths refer to distant effects on the emotions, and subsequently on
behavior.  That is, the perceptions of the moon by sensory inputs (mainly
vision) have access to the emotional circuits which thereafter effect
behavior and feelings.  There is no evidence at all that gravitational pull
can influence our brains any more than it does rocks or a bucket of water
the size of our brains.  The gravitational pull of earth is much greater
than the moon, and the earth's effect causes us to fall down.  Mechanical
disturbances of the brain or cerebrospinal fluid can effect blood
circulation to the brain if these disturbances are strong enough.  As you
learn more about the brain you will be astounded to find how many
interesting things the brain can do and can respond to, but all of these
can be ascribed to known neuroelectric and neurochemical processes.