Tetrode (biology)

A tetrode is a group of wire bundles used in electrophysiological studies in the neurosciences to record extracellular field potentials from nervous tissue, e.g. the brain. They consist of bundles of 4 thin (e.g. 30 µm diameter) wires glued together. The idea is that the wires are spaced close enough to each other to detect overlapping populations of neurons, but wide enough so that the exact waveform of the individual neurons are different on each of the wires. These differences can then be used to cluster individual neurons from the population of spikes.

Clustering

Clustering techniques involve both examining the waveform of individual spikes, and examining the spike height across all four channels.