Population spike

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Population spike (PS) is the summed electrical signal that appears when many neurons fire together in response to synaptic input. It reflects synchronized action potentials and is a type of field potential.

In the hippocampus and some other brain areas, neurons are arranged so they receive inputs in the same region and are oriented similarly. This causes the electrical signals from their spikes to add up rather than cancel, making the population spike easier to detect.

PS is usually recorded with an extracellular electrode placed near the neurons’ cell bodies or along their axons. Early interpretations of hippocampal field potentials were developed by Per Andersen.