The neuron as an analog NOT digital system

Jim Nash jimnash at
Thu Aug 10 14:29:49 EST 1995

In article <40787d$q6n at>, ma2 at (Marc
Anton) wrote:

>      Many scientists and philosophers today seem to be guilty of
> something I'll call "neural
> reductionism", a contemporary epistemic malady where otherwise
> infinitely complex neurons are "reduced" to the simple on and
> off firings we'd like to associate with today's computers.
>      Though we tend to think of the neuron as essentially
> a digital processor (with its on and off firings) it's really
> closer to an analog processor with infinitely complex chemical
> and electrical functions above and beyond anything capable with
> digital reductionism.
>      Everyone has heard how neurons function as digital-like
> on and off signals, but I'd like to hear more on how they're
> more analog than digital, e.g., the signals will vary in 
> intensity and frequency, as well as the chemical aspects which
> evade simple signal non-signal depictions.

The current view of neurons is more of a frequency coded device that has
summed or multiplicative inputs that are either analog and slow (non
junction) or frequency encoded and fast (junctions).  Frequence encoding
can be represented by an analog number and hence the current view of
nerves is essentially analog.

Reducing nerves to a digital system is a little like taking means and
variance as a measure of electrical activity where these are gross
simplifications of a complex ionic channel phenomena.  One has to reduce
to be able to model.  One has to model to gain insight.  One can only
attempt not to extrapolate far beyond the assumptions.  But now we are
talking about the scientific method not nerves.  Reduction is the weakness
and power of science.  It can't be helped.

- Jim

James W. Nash, Synergistic Research Systems
4409 Mahan Court, Silver Spring, MD 20906, USA
(301) 942-6601, fax: (301) 942-6656

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