Hemispheric control....

MS marshmallow5 at yahoo.com
Mon Jan 22 09:49:15 EST 2001


I'm assuming what you mean by contralateral control is that the left
hemisphere governs motor and sensory functions for the right side of the
body and vice-versa. The only explanation that I have found suggests that
it's a result of the visual system.  All of the other sensory and motor
systems could hypothetically be represented ipsilaterally (i.e. left side of
the body on the right side of the brain, etc.)  However, an optical property
of the visual system is that the images reaching the retina are upside down
and backwards, so that the left visual field reaches the right hemisphere,
etc.  The rest of the senses (and motor systems) have to be aligned
accordingly, so that things seen in the left visual field are also felt in
the left visual field, and reached for the same visual field. So basically,
the reversed visual system causes everything else to need to be reversed.

Marcello Spinella, Ph.D.


Andrew T. Austin <slightlynervous at NOSPAMbtinternet.com> wrote in message
news:942lop$5j14 at eccws12.dearborn.ford.com...
> This might be a silly question, but can anyone tell me what the advantage
of
> having contra-lateral control is?
>
> What benefit IS there by having the left hemisphere controlling the right
> side and vice versa?
>
> Thanks in advance,
>
> Andrew "clicking his amygdala" Austin.








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