From: John K Clark (firstname.lastname@example.org)
Date: Sun Nov 22 2009 - 13:42:40 MST
On Sun, 22 Nov 2009 "Luke" <email@example.com> said:
> Matt Mahoney: Where does this 10**9 (10**15) come from again?
> Is that the full storage capacity of the brain?
> Something like (num_synapses * num_possible_weights_per_synapse)?
I'm not Matt Mahoney but I'll give it a try. Assuming as seems likely
that memory works by Long Term Potentiation (LTP), you can make an
estimate of the maximum storage capacity of the brain. There are about
10^11 neurons in the brain and each neuron has about 10^4 synapses. I
have not seen any evidence that LTP can store more than one bit so that
gives us a figure of about 10^15 bits or 10^14 bytes of storage capacity
for the human brain.
However this is almost certainly a considerable overestimate, I don't
know the true figure but it must be less than that. In the January 28
1994 issue of Science Dan Madison and Erin Schuman found that LTP
spreads out over a large area so you have lots of copies of the same
thing. Neural Net expert Terrence Sejnowski said of this "Instead of
thinking of a synapse as representing a piece of information you can now
begin thinking of a population of potentiated synapses acting together".
John K Clark
the work of In the January 28 1994 issue of Science.
-- John K Clark firstname.lastname@example.org -- http://www.fastmail.fm - A no graphics, no pop-ups email service
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