Event-related potentials of the rat during active and passive auditory oddball paradigms.

Event-related potentials (ERPs) of the rat were recorded at the frontal, temporal and parietal areas on the skull during active and passive auditory oddball paradigms, and consisted of P1 (12.7-37.7 ms), N1 (40.0-80.6 ms), P2 (91.7-202.7 ms), N2 (183.7-246.7 ms) and P3 (265.7-462.7 ms) components. Topography and relationship to the paradigm and stimulus types were examined, and unique features were found for each component. P1, N1 and N2 were prominent frontally. However, P2 showed maximum amplitude at the parietal area. N2 and P3 were consistently present only for rare stimuli. During the passive paradigm P3 had a tendency to be greater at the parietal area, but during the active paradigm it had a longer latency and a larger amplitude than during the passive paradigm. No significant difference between the recording sites was observed for P3 latency and amplitude during the active paradigm. The relationship to the paradigm and stimulus types indicates that the rat P3 corresponds to that of the human. There are differences, however, in surface distribution of the ERP components between the rat and the human. The topographical characteristics of the rat ERP, which are possibly due to differences in brain architecture and function, should be taken into consideration when the rat is used for ERP research.