Imaging Response Inhibition in a Stop-Signal Task: Neural Correlates Independent of Signal Monitoring and Post-Response Processing

TLDR

Inhibitory control is essential for higher cortical functions to restrain habitual responses and adapt to changing task demands. The study aimed to identify the neural correlates of response inhibition during a stop‑signal task using fMRI. Participants performed a stop‑signal task with frequent go cues and infrequent stop signals; fMRI data were compared between successful and failed inhibitions and between subjects with short and long stop‑signal reaction times. Efficient inhibition (short stop‑signal reaction time) was linked to increased activation in superior medial and precentral frontal cortices, which negatively correlated with reaction time, while groups did not differ in failure rates or monitoring, indicating these regions underlie response inhibition independent of other cognitive or affective processes.

Abstract

Execution of higher cortical functions requires inhibitory control to restrain habitual responses and meet changing task demands. We used functional magnetic resonance imaging to show the neural correlates of response inhibition during a stop-signal task. The task has a frequent "go" stimulus to set up a pre-potent response tendency and a less frequent "stop" signal for subjects to withhold their response. We contrasted brain activation between successful and failed inhibition for individual subjects and compared groups of subjects with short and long stop-signal reaction times. The two groups of subjects did not differ in their inhibition failure rates or the extent of signal monitoring, error monitoring, or task-associated frustration ratings. The results showed that short stop-signal reaction time or more efficient response inhibition was associated with greater activation in the superior medial and precentral frontal cortices. Moreover, activation of these inhibitory motor areas correlated negatively with stop-signal reaction time. These brain regions may represent the neural substrata of response inhibition independent of other cognitive and affective functions.