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Brain utilization

Jason Ebaugh ebau0002 at tc.umn.SPAMNOT.edu
Wed Feb 24 23:02:46 EST 1999

The "you only use 10% of your brain" nonsense came about from the fact
that people have lost 90% of their brain in accidents and their heart
still beated, they could breath, and they could still crap their

Nuronal tissue is very expensive physiologically, and evolution would
never select for the 90% that supposedly isn't used.

I remeber a 3rd grade teacher I had that used to us that we only used
10% of our brain in a way that seemed like we were supposed to feel
guilty about it or something.

It is a wives tale, utter nonsense.

"David B. Held" <dheld at uswest.net> wrote:


>  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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