Electrophysiological correlates of motion priming: A combined ERP/TMS study

Priming of motion direction is related to the intertrial storage of the previously presented direction of motion. This effect depends upon the functional integrity of extrastriate cortex V5/MT (Campana et al, 2006 Cerebral Cortex 16 1766 - 1770). The aim of the present combined rTMS/ERP study was to gain insight into the neural correlates of the time course of the perceptual stages that subserve motion discrimination. The results showed a disruption of priming when TMS was delivered over area V5/MT, accompanied by enhanced amplitude of both the N1 and N2 components only for the priming condition. We interpret the increased N1 to reflect the greater resources necessary to process visual stimuli to overcome the effects of TMS when a stimulus shares the same direction as the previous one. The TMS-dependent enhancement of N2 may be associated with an impairment of cortical mechanisms that are specific for priming and related to an automatic search in visual memory for previously seen stimulus.