Re: Bipedalism and theorizing... was Re: Morgan and creationists

HARRY R. ERWIN (herwin@osf1.gmu.edu)
5 Aug 1996 22:08:40 GMT

Paul Crowley (Paul@crowleyp.demon.co.uk) wrote:
: In article <4tibn9$8gl@portal.gmu.edu>
: herwin@mason2.gmu.edu "HARRY R. ERWIN" writes:

: > 2. The issue of motor programs is a lot more important than
: > non-specialists are aware. [..]
: > obstacles, using somatosensory and tactile afference. When a gibbon is
: > swinging along at speed, almost all of the computation is going on in the
: > spinal cord with practically no input from the head. If you've ever seen a
: > decorticated cat preparation walk, you know what I mean.

: I haven't seen this. Is it the same sort of thing as the walking
: of a headless chicken?

Even more gruesome. With the application of various levels of generalized
stimulation, the Russians were able to get the animal to change gaits.

: Do you mean that a decorticated gibbon would brachiate?

We talked about that in class. Probably not, since the substrate is
discontinuous. The final exam was to design your own animal and develop
its motor program. I chose to do a finger glider (primitive ancestor of
bats). Got an A.

: Would the bipedal motor automatic response have reached our spinal
: cord? I have never heard of a soldier whose brain has been shot
: away continuing to walk forward. If it were to happen it would have
: done so thousands of times in, say, WW1.

Good question. It was a difficult preparation. I wonder if the NKVD tried it.

: My own (utterly ill-informed) suspicion is that bipedalism has not
: had enough time to get integrated into our spinal cord, and that
: much the same would apply to the brachiation of a gibbon.

That integration is needed for running or almost any fast movement.

: > The implication is that a major change in locomotor adaptation involves
: > changing those motor programs.

: Paul.

--

Harry Erwin, Internet: herwin@gmu.edu, Web Page: http://osf1.gmu.edu/~herwin 

49 year old PhD student in computational neuroscience ("how bats do it" 8)

and lecturer for CS 211 (data structures and advanced C++)