Stop-signal inhibition disrupted by damage to right inferior frontal gyrus in humans

The precise localization of executive functions such as response inhibition within the prefrontal cortex (PFC), although theoretically crucial, has proven to be controversial and difficult. Functional neuroimaging has contributed importantly to this debate, but as human cortical lesions are seldom discrete, the literature still lacks definitive neuropsychological evidence that a specific region is necessary for task performance. We overcame this limitation by using a new observer-independent method to relate the degree of damage within a specific prefrontal region to performance on a stop-signal task that is sensitive to the neurodevelopmental aspects of stopping behavior and to attention-deficit/hyperactivity disorder (ADHD) as well as its amelioration by methylphenidate.