My new thought.

Richard Norman rsnorman at
Fri Feb 23 09:36:26 EST 2001

One major problem with your idea is that nerve cells are really quite
tightly packed.  If you could, for example, eavesdrop on a peripheral
nerve from some distance and actually see all the action potentials,
you still have the monumental problem of separating the activity in
one cell from that of another which lies only a few hundredths of a
millimeter away.   Somehow you would have to interpret what the
nerve activity "means" rather than identify activity purely by location.

This could be done by recording all the signals in a large
3-dimensional region over time.  You could then associate the
source and destination of each nerve impulse, as well as its
conduction velocity, to give you what you need to interpret
just what the signal means (not really, but without too much
suspension of disbelief!).  Nerve signals do produce electrical
and magnetic fields.  Suitably advanced detection devices
coupled with incredibly powerful computational ability might
give you a credible basis for what you want to do.

Recording motor activity is much easier, the muscles are larger
and often widely separated.  So you could monitor the movements
that someone makes, but interpreting their sensory input would be
more difficult.  And copying that activity to another individual would
be even trickier -- there is no guarantee that the other person has
just the same assortment of individual neurons and certainly not
in the same exact geometric location. But I believe the recipient
of the information in your tale is participating voluntarily, so that
person could have electrodes implanted to generate the
appropriate nerve signals.  It would be a far more difficult to
stimulate someone in the way you want surreptitiously.

"MEShinder" <meshinder at> wrote in message
news:20010222230136.01945.00002497 at
> Would it be nice to read electrical impulses without intrusion... The
> as to why we can't do this currently no matter how scientifically useful
> that if you use external measurements of magnetic or electic fields there
> just too much noise. Remember, musculature also produces currents (hence
> ECG), not to mention the fact that your dealing with a great big, wet,
> conductor. Then comes the problem of picking out individual signals. This
> hard enough if you're sitting on the nerve, much less five feet away.
> However, as a fictional piece you might look into the work that's being
> with cell phones where the phones' transmission reflections off of the
body are
> sent back to the receiving station. I forget who exactly is doing this,
> their current direction was a sort of medic-alert function for cellular
> customers. I think that they can get pretty good signals for cardiac
> assessment. You could stretch this to get what you want if you could
> auto-majically filter out everything but the "pain" signals. A bit of a
> stretch, but it is fictive.

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