Event-related potentials before and after training: chronometry and lateralization of visual N1 and N2.

Event-related potentials (ERPs) were recorded from normal right-handed males in visual-matching tasks before and after training to a high level of automaticity. The amplitude and latency of the left and right hemispheric N1 and N2 components were analyzed. While changes of N1 "after training" relative to "before training" were statistically non-significant, the N2 component appeared to be a sensitive indicator of the variability in chronometry and lateralization of cerebral processes modified by training. The N2 results suggest that with practice the physiological processes underlying performance in a visual-cognitive task become more efficient, selective and localized.