Effects of visuospatial implicit sequence learning on visual stimulus processing: Evidence from event-related potentials and neural synchrony.

A previous study reported that reaction times (RTs) and the amplitude of the P1 component of event-related potentials (ERPs) elicited by visual stimuli decreased during visuospatial implicit sequence learning in the serial reaction time task, suggesting that sequence learning reduces attentional demands on visual stimulus processing. In the present study, to evaluate the replicability of the previous finding and to obtain a better understanding of how visual stimulus processing is affected by visuospatial implicit sequence learning, we measured ERPs and neural synchrony from 44 participants during a modified serial reaction time task which controlled for a possible confounding factor in the previous study (i.e., arousal). The results indicated that RTs and neural synchrony of the lower frequency band (22-34 Hz) decreased for a learned sequence, whereas no significant effects on the amplitudes of P1, N1, and P3 components of ERPs were observed. These results suggest that attentional demands on visual stimulus processing can be reduced by visuospatial implicit sequence learning, as suggested by the previous study, but stimulus-locked ERPs may not be sensitive enough to reflect such learning effects.