[simonster]

A "channel" usually means an individual contact on the device from which you can record a signal. A single channel may record "spikes" (action potentials) from dozens of neurons, but of those typically only 0-3 are distinguishable, depending on how close the electrode is to the neurons and how close the spike shapes are to each other. With ordinary metal electrodes, one can usually isolate action potentials from an average of 1-1.5 neurons per electrode.

However, not all channels are created equal. High channel count arrays typically have high contact densities. If the contacts are very close to each other (<100 microns or so), adjacent channels may record signals from the same neurons. I'm not entirely sure how this will affect the actual number of neurons one can isolate, but I'm eager to see. The contacts will record signals from fewer neurons than if the density were lower, but the increased density may make it possible to isolate signals that would otherwise be lost to noise, and will certainly make the process of determining which action potentials came from which neurons simpler.