Dual neural mechanisms of sustained response inhibition: Right-lateralized core control and left-lateralized adaptive support

Sustained inhibition is critical for adaptive behavioral control in complex environments, yet its neural underpinnings remain poorly understood. Using a sequence-selective stop-signal task, we hypothesized that increasing stop-signal delay (SSD) would elicit distinct behavioral dynamics and recruit dissociable neural systems supporting different stages of sustained inhibition. fMRI data from 26 participants across three SSD conditions (no-, short-, and long-delay), combined with an activation likelihood estimation (ALE) meta-analysis of 64 classical stop-signal studies, enabled us to contrast sustained and transient inhibition. Key behavioral results revealed a systematic decrease in response time (RT) with increasing SSD, while inhibition execution time (IT/ET) followed an inverted U-shaped pattern. Neuroimaging findings demonstrated that sustained inhibition engages a significantly broader bilateral network compared to transient inhibition, spanning prefrontal, parietal, and subcortical regions. Further analyses revealed a dual-mechanism inhibitory network in which early go-stop competition recruited bilateral inhibitory regions, with the left hemisphere providing complementary support, whereas late-stage emergency stopping relied primarily on a right-dominant prefrontal pathway. Together, these findings establish sustained inhibition as a distinct and dynamically organized control process, providing a novel framework for understanding how the brain flexibly regulates behavior under evolving temporal demands.