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Yes it is encoded. Essentially the rate of firing for a neuron encodes an exponential value to be represented. This is called "spike trains".

You can see this clearly if you do an extreme slowdown of a human movement. Then, suddenly, what looks like a smooth movement, like raising an arm (and because of inertia it is smoothed of course), isn't really smooth. A pulse arrives in the muscle, and there is 20ms where the muscle is tensioned, and then it's back to neutral for 100ms. Then another spike arrives, another 20ms where a lot of tension is put on the muscle, the movement accelerates, and the muscle goes back to neutral. It's not a continuous movement at all.

https://en.wikipedia.org/wiki/Biological_neuron_model

But odds are good that it's not just the value that's encoded. Many experiments have shown that it matters a lot if the signals are in phase (ie. they encode the same or some multiple of a value, but that the signals started at the exact same time matters, maybe more than the value itself. Or in the encoding: while for the value only the distance between 2 spikes matters, if 2 spikes on 2 different neurons occur at the exact same time, this will be interpreted as very relevant, even those both spikes may have very different firing rates)




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