The inhibition of imitative response tendencies.

Recent neurocognitive studies show that perception and execution of actions are intimately linked. The mere observation of an action seems to evoke a tendency to execute that action. Since such imitative response tendencies are not adaptive in many everyday situations imitative response tendencies usually have to be inhibited. These inhibitory processes have never been investigated using brain imaging techniques. Former work on response inhibition and interference control has focused on paradigms such as the Stroop task or the go/no-go task. We have carried out an event-related functional magnetic resonance imaging study in order to investigate the cortical mechanisms underlying the inhibition of imitative responses. The experiment employs a simple response task in which subjects were instructed to execute predefined finger movements (tapping or lifting of the index finger) in response to an observed congruent or incongruent finger movement (tapping or lifting). A comparison of brain activation in incongruent and congruent trials revealed strong activation in the dorsolateral prefrontal cortex (middle frontal gyrus) and activation in the right frontopolar cortex and the right anterior parietal cortex, as well as in the precuneus. These results support the assumption of prefrontal involvement in response inhibition and extend this assumption to a "new" class of prepotent responses, namely, to imitative actions. Copyright 2001 Academic Press.