left-right reversal of CNS: Why?

Robert Steven steven at MSHRI.ON.CA
Tue Sep 3 23:21:31 EST 1996

>Henry... the left-right "reversal" to which you refer occurs
>ubiquitously within mammalian nervous systems for one reason...
>The nerve-fiber termination distributions that result align with the
>totally-inhibitory outputs of the cerebellum so that the problem of
>activating the muscles to move away from environmental sources of
>noxious stimulation can be resolved by "simply" minimizing the
>topologically-distributed ratios of excitation to inhibition (TD E/I)
>occurring within the neural architecture...
>This pain-avoidance problem is infinitely-large in scope... yet this
>"simple" neuroanatomical solution typically resolves it in millisecond
>time frame... so this neuroanatomy-based problem-solving strategy has
>extraordinary survival value...
>The anatomical antecedants of the the bilateral crossing phenomenon
>("decussation") can be traced all the way back to organisms exhibiting
>radial symmetry... coelenterata... jellyfish...
>ken collins

What? I didn't realize it was so crystal clear. Doesn't the fact that our
representation of the environment is reversed on our retinas play any role?

-Rob Steven

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