P300 in freely moving cats with intracranial electrodes

Nine chronically implanted cats were used in order to study the event related potentials (ERPs) of the brain with the "omitted stimulus" paradigm. The cats were not restrained and not conditioned, could behave freely in a soundfree room. Due to a selective averaging method a P300 like of response component could be detected in the hippocampus, auditory cortex and reticular formation. The most robust and ample component was the N200-P300 wave complex of the hippocampus. The results are interpreted as follows: the P300 component in the cat brain has probably distributed generators with various frequency selectivities. The hippocampal ERP has a strong theta response component, whereas the auditory cortex and reticular formation have more marked 10 Hz responses.