A picafina device that is an electrode for measurement of neuron electrical activity where the number of measurement points is very large, and methods of selecting a subset of available measuring electrodes on the surface of the device. The device can keep the selection for a predetermined length of time, or for an indefinite length of time, both under control of the researcher or the neurosurgeon. Selecting a different measuring pad, or a combination of pads, is equivalent to making measurement at a different location or on a nearby neuron. Several parallel measurements can be made, in which case correlations can be made between the firing of different neurons.
