P300 wave elicited by a stimulus-change paradigm in acutely prepared rats.

Presentation of a long sequence of stimuli in one modality followed by infrequent substitution of stimuli in a different modality produced a very large P300 wave in the evoked potential to the infrequent stimulus. The P300 wave was never observed in a repetitive train of stimuli in one modality or to the background stimuli during the stimulus change procedure. This phenomenon was observed in cortical recordings from anesthetized rats. This P300 wave corresponds in latency to that observed in human cognitive studies, and the use of this paradigm in animal studies could greatly facilitate work to determine the neural basis of the P300 wave.