Very low amplitude muscle activity increases probability of motor evoked potentials in healthy individuals and in ALS - TMS-EMG dataset

Single pulse transcranial magnetic stimulation (TMS) with electromyography (EMG) data recorded from right hand abductor pollicis brevis (APB), recorded as reported in O'Sullivan et al., 2026 (doi: 10.1101/2025.08.07.663223) and McMackin et al., 2024 (doi: 10.1016/j.cnp.2024.03.001). Data include: subjectType: Control (C) or person with ALS (P) subjectID: Unique letter code corresponding to each participant normalisedStimulusIntensity: Unitless proportion calculated as stimulus intensity (% of maximum stimulus intensity) divided by resting motor threshold (% of maximum stimulus intensity) selected by threshold tracking. rmsBaseline_demeaned: Each EMG epoch (spanning 500ms before to 500ms after pulse delivery) was demeaned by subtracting the mean signal amplitude across the 500ms prior to pulse delivery. Subsequently, rmsBaseline_demeaned value was calculated as the root mean squared amplitude of EMG recorded from APB in the 200ms immediately prior to stimulation. Peak-to-peak amplitude exceeds 50µV?: Whether the peak-to-peak amplitude of the motor evoked potential (between 15 and 50ms following stimulation) exceeded 50µV.