Fig. 1.

Experimental setup, protocol, and representative data. A: experimental protocol. B: grip device. C: electromyographic (EMG) activity from the first dorsal interosseus (FDI) muscle, grip force exerted by thumb and index finger, and motor-evoked potentials (MEP) elicited by transcranial magnetic stimulation (TMS) at the instant of the go cue for the high-force (HF) and low-force (LF) trials (1 representative subject, experiment 1). The baseline MEP was obtained by delivering TMS in between trials while the subject was at rest (see text for more details).