Action related sounds induce early and late modulations of motor cortex activity

It is now well established that the human brain is endowed with a mechanism that pairs action perception with its execution. This system has been extensively studied using visual stimuli and recent evidence suggests that it is also responsive to the sound of motor actions. Here, we presented action (finger and tongue clicks) and acoustically matched sounds to investigate action-related sound processing in a 12-year-old child undergoing intracranial monitoring of epileptic seizures. Electroencephalography grids were located over a large portion of the right hemisphere, including motor cortex. Wavelet analysis carried out on electrodes overlying the functionally defined hand representation of the motor cortex revealed early (100 ms) and late (250-450 ms) decreases in mu rhythm power (12 and 20 Hz) selective for natural finger-clicks compared with control sounds. These data suggest the presence of a rapid, multimodal resonance mechanism modulating motor cortex activity.