Short-Term Practice Modulates ERP Components Without Behavioral Change in a Short-ISI Go/NoGo Task

Background/Objectives: Response inhibition, a core aspect of executive function, is commonly evaluated using the Go/NoGo task. While previous research has demonstrated that short-term practice can influence both behavioral and neural markers of response inhibition, the role of task difficulty—particularly when manipulated through short interstimulus intervals (ISIs)—remains underexplored. This study investigated the effects of short-term repeated practice on behavioral performance and neural activity during a high-difficulty Go/NoGo task with a short ISI. Methods: Fifteen healthy young adults completed a visual Go/NoGo task in four repeated sessions within a single day. The task involved a 600 ms ISI, 100 ms stimulus duration, and a 20% NoGo stimulus frequency. Behavioral outcomes included response time (RT) and error rate (ER). Neural activity was recorded via electroencephalography (EEG), focusing on event-related potentials (ERPs) associated with response inhibition, specifically the NoGo-N2 and NoGo-P3 components. Results: No significant changes were observed in RT or ER across sessions, indicating no improvement in behavioral performance. Similarly, NoGo-N2 amplitudes remained stable. However, a significant reduction in NoGo-P3 amplitude at the Fz electrode was found in later sessions, suggesting decreased frontal cortical engagement in response inhibition. Conclusions: Although short-term repeated practice of a high-difficulty Go/NoGo task did not enhance behavioral performance, it was associated with reduced neural activity related to response inhibition. These findings suggest that neurophysiological adaptations may occur even in the absence of observable behavioral changes, particularly under high task demands.