IUBio

"Humans only use a fraction of their brain...Reply"

maxwell mmmaxwell at hotmail.com
Fri May 18 04:46:47 EST 2001


Bill Saidel <saidel at crab.rutgers.edu> wrote in message news:9e1qqm$bi7$1 at crab.rutgers.edu...
> Years ago (maybe 12 by now) I posted a message asking this question
> on a fledgling neuropsych listserver. I asked where such an idea
> originated from and received a few answers, none of which directly
> answered the question. 
>    One answer from McCarthy of AI fame was that in 1939 or so (he
> was not sure), he read the famous myth in a self help book.  At
> least two others suggested Wm. James and Karl Lashley as possible
> sources. 

You're getting warm. Lashley's ablation studies were likely the
*inspiraton* for the unknown myth-maker. 

>    Lashley's work with rats and cortical lesions seems the most 
> "logical" source if I had to invent one, but his work on this 
> subject for many reasons (as is the myth) is odd because he seemed
> to have ignored the cortical literature arising from the 60 years
> previous to his (ca.) 1929 Science review paper. 

Have you actually read the 1931 article: "Mass Action in Cerebral Function?"
(from page 246, in Science, New Series, 273(1888):245-254 [March 8,1931])
|| From the standpoint of an adequate cerebral physiology, also, the classical concept
of cerebral localization is of limited value, because of its static character and its
failure to provide any answer to the question of how the specialized parts of the cortex
interact to produce the integration evident in thought and behavior. The problem here is 
one of the dynamic relations of the diverse parts of the cortex, whether they be cells
or cortical field. || 

Here we saw Lashley raising objections that the previous (Golgi stain, and crude electrode stimulations, mainly) mappings did not suffice to account for CNS functionality.
He was objecting to the inferences being offered without knowledge of real activity,
and sought to investigate by using ablation, a well-considered choice since the methodology
at the time had not reached even to such fineness of scale as the giant squid axon required.

...you were claiming he "seems to have ignored"   .   .   .. ..


>    Anyway, much work in the last 50 years tends to support cortical
> functional localization which Lashley apparently ignored. 

Apparently not:

 || The localization of the visual field is as precise and as absolute as it is in man ||
(page 247)

Twice you said he "apparently ignored." 
Why would a seemingly intelligent person like yourself
posit anything about Lashley without troubling to read his paper? 
It's not obscure, or anything. 
Whoops.  

|| It is not inconceivable that the cortex determines the reactions of lower centers, 
not by activating individual cells or cell groups, but by determining the general degree
and direction of polarization. || (page 252)

Here we saw one of the first truly intelligent attempts to account for the fact that subcortical
structures (such as cerebellum, which Lashley left un-ablated, and basal ganglia, which
the illustrations leave indeterminate as to degree of destruction) can suffice in tasks.

The myth then  arises, in my interpretation of an urban legend, from studies
> based on mistaken notions of the homogeneity of the majority of cortex. 

Like I said, you were getting warm-- try:
 " The myth arises from twisting a most refreshingly honest and well-reasoned
 account into a 'straw man' for the purpose of attack"   --Will my phrase suffice?

>    However, one can take this statement de novo and ask what
> does it mean? I wonder if the question even has meaning?

Now you're back on good ground !

> 
> Is it similar to "A radio only operates at a miniscule of efficiency
> because it is only receiving one station at a time?" or
> "Computers are inefficient because many of the virtual switches
> are closed at a given instant of time?"  

Yes, except put some broad-frequency static on the radio, and randomize
the non-task-commandeered computer switches on a low duty cycle, and you're close.

>    I think the %10 question is invalid at least because it does 
> not specify the nature of neural information. Is information only
> conveyed by active neurons? Surely not! Just think about any 
> topographic system requires the "inactivity" of most neurons to 
> permit specification of a specific item within the topography 
> (and I use "inactivity" to mean uncorrelated, not silent).

You got your A ! 

>    Not to belabor the point, and I sure anticipate both cogent and 
> flamed responses, despite the ubiquitous "knowledge" that humans
> use only 10-15% of their brains, that knowledge is bogus.

 The '10%' notion was never anything but crap, and bespoke
the kind of 'neurological' opacity that would consider a hit on the head
to be a valid approach to stimulation.

It is remarkable that such IDIOCY still has ANY currency, but one will never
go hungry by betting on the stupidity of common people, alas.

--maxwell 

> 
> Bill Saidel
> Biology, Rutgers University
> saidel at crab.rutgers.edu 





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