Event-related potential (ERP) waveforms and topography of the P300 component.

<p>Upper panels show grand-averaged ERP waveforms from 3 midline electrodes (Fz, Cz, and Pz), and lower panels show topographies of voltage distributions at P300 epoch. P300 was widely distributed in centroparietal regions at 350–450 ms poststimulus, as indicated by arrows in upper panels. For RLS group, the marginally significant reduction of P300 amplitude and significant delay of P300 latency were observed. <i>Post hoc</i> pairwise comparison revealed that P300 amplitude was significantly reduced for RLS group at frontal and central regions compared to normal group.