Magpro r30 stimulator

TMS was applied with a MagPro R30 stimulator (MagVenture A/S, Farum, Denmark) and a figure‐of‐eight TMS coil (MC‐B70; inner radius = 10 mm, outer radius = 50 mm). Pulses were biphasic, with an anterior–posterior followed by posterior–anterior current direction in the brain. The coil was placed tangentially to the scalp over the electrode position P4 (based on the international 10–20 system) with the handle in posterior direction orienting 45° away from the midline. The cTBS protocol consists of a total of 600 stimuli applied in bursts of three stimuli at 20 ms intervals (50 Hz), with bursts repeated at 200 ms intervals (5 Hz) (Huang et al., 2005 (link)). Stimuli were given at an intensity of 100% of the individual resting motor threshold (mean stimulation intensity = 33.9% of maximum stimulator output, SD = 5.3, 46.8 A/μs). Resting motor threshold was determined using single pulse TMS over the right motor cortex. It was defined as the lowest intensity that elicited an observable muscle twitch of the left index finger on three of six trials (Pridmore et al., 1998 (link); Varnava et al., 2011 (link)).
During sham stimulation, the coil was held at 90° to the participant's skull, so that no pulses perturbed underlying cortex (Hilgetag et al., 2001 (link)).

A MagPro R30 stimulator (MagVenture) with a butterfly coil (MC-B70) and dimensions (169 × 112 × 16/33 mm) was used to induce motor-evoked potentials (MEPs) from the right first dorsal interosseous (FDI) muscles. The coil was placed over the left M1 region with a posterior–anterior orientation and set at an angle of 45° to the midline. The area of stimulation with largest MEP responses was defined as the hotspot and marked on the scalp to ensure consistency of coil placement throughout the experiment. Resting motor threshold (RMT) was defined as the minimal stimulator output needed to elicit three out of six MEPs with minimum amplitude of 50–100 μV in a relaxed FDI muscle (Rossini and Rossi, 1998 (link)). All raw EMG signals, were amplified, filtered (20 Hz–10 kHz) and recorded with a PC running a commercially available data acquisition and automated-analysis package (PowerLab^TM ADInstrument 4/35 with LabChart^TM, Australia) for offline analysis.

Biphasic TMS pulses were applied to the cortex via a figure‐of‐eight cooled coil connected to the MagPro R30 stimulator with a MagOption unit (Magventure, Denmark). The TMS coil was held over the scalp, with the handle of the coil pointed backwards, angled approximately 45° from the midsagittal line and held perpendicular to the presumed direction of the central sulcus. In a single session, active TMS was applied to the left motor cortex (to ascertain the appropriate stimulation parameters) and this was followed by stimulation of the right dorsolateral prefrontal cortex (PFC) and the left dorsolateral PFC. The order of the stimulation site (right before or after left dorsolateral PFC) was counterbalanced across participants.