A unique Go/No-go task reveals specific inhibition-related activation in the right IPS

摘要

Introduction: Response inhibition - the ability to suppress inadequate but pre-potent response tendencies - is a cognitive-motor effortful process, in the realm of cognitive control. Interestingly, impaired response inhibition has been suggested as a key component in disorders such as ADHD. However, the brain mechanisms typically reported for response inhibition are extensive and provide poor markers for investigating atypicalities. Methods: We used rapid event-related functional magnetic resonance imaging (fMRI) to investigate the neural mechanisms underlying response inhibition in healthy controls. Participants performed a novel Go/No-go task that minimizes intervening factors such as perceptual complexity and working memory, while emphasizing attentional components. Manipulation of the frequency of targets, from 25% to 75%, enabled us to create a contrast of No-go trials at different frequencies. This contrast is expected to isolate inhibition-related activity while eliminating the involvement of motor, perceptual and working memory components. Results and discussion: Unlike previous reports, which in most cases contrasted No-go trials with Go trials and yielded activations in widespread fronto-parietal networks, our unique design allowed us to isolate a distinct cluster of activation in the right intraparietal sulcus (rIPS). Our findings suggest that the rIPS may serve as a potential neuroanatomical marker for response inhibition. In future studies we will utilize this marker, comparing the neural response in participants with and without ADHD, and investigating the relation of this focal activity to behavioural measures and symptomatology of attention deficits.