Response inhibition is driven by top-down network mechanisms and enhanced with focused ultrasound
AbstractResponse inhibition is necessary for humans to safeguard against undesirable action consequences. Inhibitory control consistently recruits the prefrontal right inferior frontal gyrus (rIFG) and pre-supplementary motor area. Yet, whether inhibitory control is a defining function of rIFG, distinct from attentional orienting, remains widely debated. The issue emerges from previous studies reporting inhibitory and attentional demands both elicit rIFG activation. Here, we address this issue based on the proposition that inhibitory and attentional control are predicated on different network mechanisms. We derived and causally tested network mechanisms using EEG, dynamic causal modeling (DCM) and focused ultrasound stimulation in humans performing a Stop-Signal task. rIFG stimulation increased inhibitory performance and speed. DCM of evoked responses linked behavioral inhibition to rIFG top-down gain modulation of pre-SMA inhibitory populations. These results reconcile competing accounts of prefrontal cognitive control function, by identifying rIFG-based inhibitory mechanisms as distinct from other top-down cognitive control processes.