Sensorimotor attenuation by central motor command signals in the absence of movement.

Voluntary actions typically produce suppression of afferent sensation from the moving body part. We used transcranial magnetic stimulation to delay the output of motor commands from the motor cortex during voluntary movement. We show attenuation of sensation during this delay, in the absence of movement. We conclude that sensory suppression mainly relies on central signals related to the preparation for movement and that these signals are upstream of primary motor cortex.