Abstract
To clarify the difference in cognitive processing between Go/NoGo and Stop/NoStop tasks, participants (N=50) were presented with pictures belonging to five different categories. Under the Go/NoGo task, they were required to press a button for only people, whereas under the Stop/NoStop task, they had to inhibit responses for only cars and react to all other stimuli including people. Event-related potentials recorded in the two tasks revealed a large, biphasic positive wave (P3) : a parietally maximal subcomponent with a peak latency around 300 ms and a more broadly distributed subcomponent peaking after 400 ms. The early and late P3s, whose distributions and latencies were analogous to the two positive P-SR and P-CR waves (Falkenstein et al., 1994) were interpreted to reflect stimulus evaluation and the following motor-response processing, respectively. The correlations of early and late P3 amplitude at Fz with reaction time were observed for the NoStop stimuli, but not for the Go stimuli. These findings suggest that motor-response processing might play a more important role during the Stop/NoStop task, compared to the Go/NoGo task. (Japanese Journal of Physiological Psychology and Psychophysiology, 22 (3) : 225-236, 2004.)
