Response inhibition is more effortful than response activation: behavioral and electrophysiological evidence.

The present study aimed to measure the response inhibition by embedding a secondary probe task within a Go/NoGo paradigm. The response time for the probe and the time course of the discrimination process for the probe shown by event-related potentials were measured to investigate the effect of response inhibition. The results showed that the probe response time were longer for the NoGo-probes versus Go-probes, indicating a more cognitively demanding process in processing NoGo stimuli. The event-related potential results showed that the NoGo stimuli evoked a more positive frontal P3 component relative to the Go stimuli. Compared with the NoGo-probes, the Go-probes evoked enhanced N1, but decreased P2 and P3 components over frontocentral scalps, indicating increased orienting process, but decreased selective attention process for the Go-probes. These results indicated that response inhibition (NoGo) was more cognitively demanding than the response activation (Go).