Re: human brains v.s animal brains

Barry Mennen (barrym2@ix.netcom.com(Barry)
9 Dec 1996 03:11:07 GMT

In <Pine.SOL.3.95.961206160124.6005B-100000@taurus.cus.cam.ac.uk> Jane
Andrews <mja1002@cus.cam.ac.uk> writes:
>
>Brain size is normally compared using a measure called encephalisation
>quotiant (EQ). This gives a value for the size of a species' brain in
>relation to that expected for a mammal of that body size. The
referent is
>refered to as a basal mammal, (a hypothetical ancestoral incectivor I
>think) but it doesn't really matter what the comparison is with so
long as
>it remains constant. So while humans of course have smaller brains
that
>elephants, we have very large brains in comparison with that which
would
>be expected for a mammal of our size, about four times bigger in fact.
>As an aside, it's interesting to note that living humans have smaller
>average cranial capacity than pleistocene amh.
>
>There are also other consideration.
>the shape of the brain may be as important as size. humans have a
very
>high proportion of neocortex. The question of shape is particularly
>interesting when comparing modern humans and neanderthals.
>Neanderthals had larger brains than modern humans, but they also
differed
>in shape, being more developed in the occipital region and less so in
the
>frontal region ( don't ask me what this signifies !).
>
[some minor snippin]
>
>Jane Andrews.
>

Jane--
The occipital bun of the Neandertals is composed of enlarged
cerebellum--the switchboard for muscualr control--the N's were about
30% more muscular than us and needed more cerebellum to control the
added bulk.

Cheers,

Barry M.