Fig. 5.

Biceps EMG recordings from an individual subject when the response to transcranial magnetic stimulation (TMS) was timed to arrive at the onset of the M2. Responses during the “do not intervene” (DNI) task instruction are shown in gray, while those during the “oppose the displacement” (FLEX) task instruction are shown in black. Below each trace are the equivalent responses elicited when the joint perturbation was given without cortical stimulation. The traces are an average of 10 responses for the combined TMS and stretch reflex conditions and an average of 20 responses for the joint perturbation in isolation. The onsets of the M1 and M2 are indicated by the arrows