M and P components of the VEP and their visual field distribution

To study components related to parallel processing of information across the visual field, multifocal pattern reversal visual evoked potentials (VEPs) were recorded using binary m-sequences. Contrast, chromatic, spatial and temporal characteristics of the stimuli were varied in order to favor contributions from either M or P pathways. Responses were decomposed into two additive components whose behavior was consistent with that of M and P mechanisms. The results suggest that contributions to the VEP from the M pathway precede those from the P pathway, and that the ratio of P/M contributions decreases with eccentricity. (C) 1997 Elsevier Science Ltd.