rscan from nycap.rr.com wrote:
> Motor programs in the brain
[snip summary]
> Some list! Since none seem to question that invertebrate motor pattern
> generators are constructed by the genome, why should we question
> similar construction by the genome in vertebrates (including man, of
> course). The shift from individual neurons to populations of neurons
> is fundamentally trivial. Also trivial (except to anatomists) is to
> extend the "brain" to include the spinal cord. I so do.
The shift to neural groups or clusters (a term I prefer to
'populations') is not at all trivial, especially since it's quite clear
that that in vertebrates environmental factors are essential to the
proper development of the brain, including of course those motor
programs. IOW, the structure of those clusters de[ends on environmental
inputs. The vertebrate learns how to move. This does not abrogate the
function of the genome, but does change it. As a matter of fact, there
is evidence that the genome's function depends crucially on external
inputs, even in invertebrates.
> I like to think that a human lifetime can be seen as the genome
> interacting with the environment.
Well, of course. What else?
[snip]
