The novelty P3: an event-related brain potential (ERP) sign of the brain'sevaluation of novelty

A review of the literature that examines event-related brain potentials (ER Ps) and novelty processing reveals that the orienting response engendered b y deviant or unexpected events consists of a characteristic ERP pattern, co mprised sequentially of the mismatch negativity (MMN) and the novelty P3 or P3a. A wide variety of evidence suggests that the MMN reflects the detecti on of deviant events, whereas the P3a is associated more with the evaluatio n of those events for subsequent behavioral action. On the scalp, the novel ty P3a, is comprised of at least two aspects, one frontal the other posteri or, each with different cognitive (and presumably neurologic) correlates. I ntracranial ERP investigations and studies of patients with localized brain lesions (and, to some extent, fMRI data) converge with the scalp-recorded data in suggesting a widespread neural network, the different aspects of wh ich respond differentially to stimulus and task characteristics. (C) 2001 E lsevier Science Ltd. All rights reserved.