In neuroscience, a population spike (PS) is the shift in electrical potential as a consequence of the movement of ions involved in the generation and propagation of action potentials.[1] Population spikes often reflect synaptically induced firing and therefore, they can be classified as a type of field excitatory postsynaptic potentials.
In some areas of the brain, such as the hippocampus, neurons are arranged in such a way that they all receive synaptic inputs in the same area.[2] [3] Because these neurons are in the same orientation, the extracellular signals from the generation of action potentials don't cancel out, but rather add up to give a signal that can easily be recorded with a field electrode.
The PS is usually recorded with an extracellular electrode placed close to neural cell bodies or axons.The first interpretations of hippocampal field potentials were developed by Per Andersen.