Age-related changes in ERP correlates of visuospatial and motor processes.

Although previous ERP studies have demonstrated slowing of visuospatial and motor processes with age, such studies frequently included only young and elderly participants, and lacked information about age-related changes across the adult lifespan. The present research used a Simon task with two irrelevant dimensions (position and direction of an arrow) to study visuospatial (N2 posterior contralateral, N2pc) and motor (response-locked lateralized readiness potential, LRP-r) processes in young, middle-aged, and elderly adults. The reaction time and motor execution stage (LRP-r) increased gradually with age, while visuospatial processes (N2pc latency) were similarly delayed in the older groups. No age-related increase in interference was observed, probably related to a delay in processing the symbolic meaning of the direction in older groups, which was consistent with age-related differences in distributional analyses and N2pc amplitude modulations.