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Brain utilization

David B. Held dheld at uswest.net
Wed Feb 24 03:57:33 EST 1999


Howdy,

  I'm "Bill Gates" that asked the neurotransmitter question before (I
was on a public computer).  Thanks for all the comments...they were
quite informative.  I have a pretty simple question that's kind of
bugged me for quite some time.  If it's in a FAQ somewhere, please send
me the location.  You hear a common citation that we only use 10% of our
brain.  Where does that come from, and what do they mean by "use 10%"?
  My guess is that "they" mean only 10% of the neurons in the brain are
firing at any one time, or that 10% of the total possible glucose
consumption is observed at any one time.  If it's the former, then I
wouldn't ever want to use 100%, because I would definitely be in a very
chaotic and fairly useless state of mind.  If it's the latter, then I
still wouldn't want to use 100%, or my brain would probably look like an
anti-drug commercial.  Who's to say what the "capacity" of the brain is,
anyway?
  I roughly estimated that if each neuron had on average, say 100
connections, and each connection stored, say a 32-bit floating point
value (the synaptic "weight" of the connection), and there were say, 10
billion functional neurons in the brain, then you could say that the
brain roughly has a capacity of 4 TeraBytes (TB) of data.  And if the
average neuron could fire, say, 300 times per second, and you considered
one firing event to be 99 summations plus a comparison operation,
resulting in 100 floating-point operations, then you could say that the
brain has a "peak operating capacity" of around 300 TeraFLOPS (TFLOPS).
That's some pretty serious power!  I think that's several hundred of 
the fastest supercomputers in existence.
  So, then, I suppose, based on average firing rates and connections,
one could come up with a third computation for "average utilization",
and try to show that it is 10% of the peak, but this seems to me to be
the least likely explanation.  What's the deal?

Dave

-- 
David Held, Chief Programmer   "As far as the laws of mathematics refer
Business Computing Solutions    to reality, they  are not  certain; and
email: dheld at uswest.net         as far as they are certain, they do not
web: www.uswest.net/~dheld      refer to  reality."  -  Albert Einstein



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