Figure 1.

Experimental set-up and procedure. (A) Flowchart of trial. Participants silently read a German verb presented on a screen. A first visual go-signal (+) instructed the participant to start speaking the invariant prefix ‘auf’ and to prolong the ‘fff’ until a second visual go-signal (!) indicated to move onto speaking the previously presented verb. To study a time window of 350 ms preceding the second speech gesture, we used 70 single pulse TMS trials per hemisphere per subject, in which we varied the interval between the single TMS pulse and the speech onset of the verb stem. (B) Traces of the electromyography with MEPs elicited in the contralateral (right) and ipsilateral (left) tongue-side by TMS of the left primary motor cortex. Stimulation intensity was 120% of the individual’s motor threshold. The lower line shows the oscillogram indicating speech onset of the particle ‘auf’ and the subsequent speech signal.