[ExI] neurons

[Tomaz Kristan]

Kaku is wrong and confused once again. The  number of possible states is
really very big. 2 or 3 to the power of neurons. However, this tells you
little or nothing. If you have a hard drive with 1 TB capacity, then the
number of possible states is 2 to the power of 8*10^12. Much more even!

And also not very useful in what he (Kaku) wants to say. This raising to
the power is unjustified and misleading.


On Wed, May 21, 2014 at 1:51 PM, Anders Sandberg <anders at aleph.se> wrote:

> Kaku seems to be talking about spiking and non-spiking states. Works for
> his purposes, since he is just making an order of magnitude argument that
> there is *way* more representational capacity in the brain than in the
> genome. A factor of ten doesn't change his conclusions much... in fact
> 4^3e9 is *way* less than 2^100e9=4^50e9 (and then to the Nth ~100 power for
> longer thoughts) and if there are more neuron states then the difference
> just becomes larger.
>
> The issue of what states there are in the brain and how much information
> is encoded in spike patterns has been discussed endlessly in computational
> neuroscience - I slept through many lectures on it back in the late 90s :-)
> The gist of it is that rate codes are somewhat inefficient since you need
> to integrate a number of spikes to learn what the value is. Timing codes
> can be super-efficient *if* you can measure timing accurately and there is
> no noise... which there is. Distributed representations are likely and
> solve a lot of problems, but assigning information content to them is
> complex. Lots of information theory going on, no conclusion that really
> stuck with me except that the brain seems to use all methods
> simultaneously.
>
> But note that the change of rate in a rate code is a pretty slow and
> tricky way of representing something. We do seem to have neurons that turn
> such changes into signals encoding the direction of change instead, which
> are presumably easier to handle.
>
>
>
> Anders Sandberg, Future of Humanity Institute Philosophy Faculty of Oxford
> University
>
>
> William Flynn Wallace <foozler83 at gmail.com> , 20/5/2014 10:46 PM:
>
> In The Future on the Mind, by Michio Kaku, he says as follows (facing page
> 342):
>
> "Define complex in terms of the total amount of information that can be
> stored.  The closet rival to the brain might be the info contained w/in our
> DNA.  Three billion base pairs containing one of four aids, therefore total
> amount of info is four to the three billionth power.  The brain can store
> much more - one hundred billion neurons, *which can either fire or not
> fire*.  Hence there are two raised to the one-hundred-billionth power
> initial states of the brain.... the states change every few milliseconds.
> A simple thought may contain  one hundred generations of neural firings.
> Hence there are two raised by one hundred billion, all raised to the
> hundredth power possible thoughts contained in one hundred generations.
> Brains are ceaselessly computing.  Therefore the total number of thoughts
> possible within N generations is two to the one-hundred-billionth power,
> all raised to the Nth power.
>
> My question concerns the underlined clause:  there are three states to a
> neuron:  increasing its rate, decreasing its rate, and staying the same.
> Kaku says that a neuron fires or not.  This seems to say that a neuron is
> idle, waiting for stimuli, whereas I think that no neuron ever is not
> firing.
>
> Am I confused again, or is he wrong?  bill w
>
>
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