Event-related potentials in a memory scan task concerned with movement directions

To study brain mechanisms of memory scan, we have measured event-related potentials (ERPs) during the execution of a Sternberg task concerned with movement directions of random dot patterns (RDPs). Five healthy male subjects participated in the experiment. Event-related potentials were recorded at 20 electrode positions over the entire head. A prominent positive ERP component peaking at 380–390 ms known as P300 was observed in the parietal region after the presentation of the probe moving random dot pattern, whereas the P300 was not observed after the presentation of a control stationary RDP. On the other hand, a positive ERP component peaking at 127 ms was commonly observed in the occipital region after the presentation of both moving and control stationary RDPs. These findings suggest that P300 may reflect cortical activities related to the memory scan of movement directions of RDP.