Re: Brain development

Anders Sandberg (
Mon, 16 Jun 1997 23:10:22 +0200 (MET DST)

On Mon, 16 Jun 1997, James Rogers wrote:

> I also remember studies of individuals who by some fault of nature were
> missing non-trivial sections of the human brain (like most of a
> hemisphere), but who otherwise were indistinguishable from normally
> developed individuals.

This is true. In my basic neuroscience course a pathologist gleefully
showed us slides of various malformed brains. You can remain normal
with some rather non-trivial damage, especially if they are in-born.
One of the more interesting types consisted of cortex embedded inside
the white matter or even turned inside out! During early development,
radial glia cells provide a scaffolding which the neuroblasts climb
to the brain surface, where they form the cortex. The lowest layers
develop first, and higher layers climb past them (another absurd
result of evolution). Under some (rare) circumstances this process
fails, and the cortex is inside out or pieces of it are left inside
the brain. According to the pathologist the victims can be quite
normal (although, as he put it, "few are Einsteins").

> >I guess this is another one of persistant scientific myths floating
> >around. Some months ago this condition was discussed on
> >bionet.neuroscience, the apparent consensus being that there is very
> >little to the original paper. On similiar vein, anybody knows where the
> >bike gang alpha with nonconvoluted brain mythoid comes from? Curious.

Sounds vaguely possible; although I buy James explanation as more

> Sounds like Fetal Alcohol Syndrome, a common symptom of which is
> significantly decreased convolution in the brain. According to my parents
> (who live in an area of Alaska where FAS is prevalent in many people),
> individuals with FAS can often be distinguished by their behavior.

There is even a certain "look" to it, with drooping eyelids and a
subtle shift in facial features. Yet another reason to avoid alcohol.

Anders Sandberg Towards Ascension!
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