Multimodal Neuromuscular Assessment Protocol

MEPs, EMG activity and SP evoked by stimulation were recorded with surface electrodes placed in the belly-tendon position with Digitimer Ltd. D360 amplifiers (gain 250, bandpass 3–3000 Hz). The first dorsal interosseous was the target muscle whose activity was recorded and sent to a CED Ltd. 1401mkII unit 1 (sampling at 10 kHz and storing signals); we also recorded activity from the extensor indicis. Finger movements were monitored using an electrogoniometer (S100) and finger force using a dynamometer (P200), both connected to a K800 amplifier (Biometrics Ltd.) and sent to CED1401mkII unit 1 for sampling (10 kHz) and storage. In parallel, the force signal was sent to another CED1401mkII (unit 2) run with Sequencer. Sequencer (sampling at 100 kHz) ran an algorithm (previously described in detail and validated^{8 (link)}) to trigger TMS at MVC peak plateaus and percutaneous nerve stimulation in the resting muscle; the transistor-transistor logic (TTL) triggers from CED1401mkII unit 2 to the stimulators were also sent to CED1401mkII unit 1 as TTL markers to facilitate offline data processing.