X-Message-Number: 7321
Date: Wed, 18 Dec 1996 11:58:40 -0800 (PST)
From: Joseph Strout <>
Subject: Re: Holographic brain nonsense

On Wed, 18 Dec 1996, CryoNet wrote:

> >                                 SHUFFLEBRAIN        
> >Lashley alsbrought along the knife. With it, he found he could dull
> >   memory in proportion to the amount of cerebrum he cut out. But if he
> >   left a rat with any cerebrum at all, the animal could still remember.
> >   Not only did he fail to amputate memory, but one area of the cortex
> >   would serve it as well as another. He came to two controversial  
> >   conclusions: intensity of recall depends on the mass of brain, but

> >   memory must be divvied up equally. "Mass action" and     
"equipotentiality" became his theme.

Lashley's experiments have been discredited for many years.  They suffered
from poor experimental design, and poor observation skills.  Cut one part
of the brain, and it hinders movement on one side -- and golly, the rat
takes longer to finish the maze!  Cut another part, and the rat goes blind
-- gee, it takes longer to finish the maze again!  Cut another part, and
the rat forgets the route -- and takes longer to finish!  Cut another
part, and the rat staggers around like it's drunk -- and takes longer to
finish!  If all you report is how long it takes to finish (as Lashley
did), then you don't know anything at all.

Moreover, from everything we understand about how memories are stored,
holograms have nothing to do with it.  They *are* stored in a distributed
and probably redundant fashion, but that doesn't mean you could
reconstruct the entire brain (or all memories) from a tiny piece.
Instead, it means that each tiny piece is meaningless without the others.

On the other hand, it does suggest a good robustness to minor damage, or
the sort of minor information loss that is likely to happen.

My $0.02 worth,
-- Joe

,------------------------------------------------------------------.
|    Joseph J. Strout           Department of Neuroscience, UCSD   |
|               http://www-acs.ucsd.edu/~jstrout/  |
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