Klarinet Archive - Posting 000802.txt from 2002/06

From: w7wright@-----.net (William Wright)
Subj: RE: [kl] Fwd: Brains
Date: Mon, 24 Jun 2002 10:21:07 -0400

Under certain conditions --- and someone in my own family is proof of
this, I've seen the cat scans with my own eyes --- the brain *can* grow
significantly (approximately 25% in this case) to good effect in order
to meet a demand. This ability drops off during the first 12 months of
life, but it is pretty well agreed by neurologists that *all* of us
retain a small fund of undifferentiated neurons that can be induced to
grow. Such neurons have been harvested and used in laboratories.

There have been several published & juried reports of speech impairment
in which --- unlike the idiotic paraphrase in the magazine article which
was quoted earlier --- the evidence is overwhelming that the patient's
speech centers did not grow because damage to the speech mechanism after
birth never gave the neurons any exercise. This doesn't prove the
reverse (that demand causes growth), but if speech centers in uninjured
patients end up being much larger, you have to suspect that the demand
for brain function had something to do with the growth.

Finally, the morphological distinction between "growing" a new neuron
and "redirecting" an existing neuron to a new connection is a fine line
indeed. If an existing neuron extends a dendrite just a little bit
further and thereby creates or enhances a connection, or if a neuron
expands one of its structures such that it secretes a bit more
neurotransmitter, do you call this a morphological change?

Cheers,
Bill

---------------------------------------------------------------------