Temporal Summation of Subthreshold Stimuli in Human Motor Axons: Implications for IONM.

This dataset supports the study “Temporal Summation of Subthreshold Stimuli in Human Motor Axons: Implications for Intraoperative Neuromonitoring” (Naidoo & Jones, 2025). The research investigates how stimulus amplitude and pulse width interact to influence the probability of compound muscle action potential (CMAP) generation from trains of subthreshold stimuli. Data include recordings from the median nerve–abductor pollicis brevis muscle in 15 healthy participants, analysed to calculate mean response probabilities, Subthreshold Susceptibility Index (SSI) values, and latent addition (LAh) metrics of persistent sodium current. The findings quantify parameter-dependent susceptibility to subthreshold activation and identify persistent sodium conductance as a partial mechanistic contributor, with direct implications for safe stimulus parameter selection in intraoperative corticobulbar motor-evoked potential monitoring.