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Brain utilization

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


  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,
  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?


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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