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Updated: Aug 10, 2026
Utilizing Transcranial Magnetic Stimulation to Study the Human Neuromuscular System
Published on: January 20, 2012
Differential cortical responses to neuromuscular electrical vs. peripheral magnetic stimulation: a multimodal
Fengyun Yu1,2, Weining Wang2, Leyi Xu1
1Department of Rehabilitation Medicine, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, China.
Objective:
To investigate cortical modulatory effects of neuromuscular electrical stimulation (NMES) and peripheral magnetic stimulation (PMS) applied to the wrist extensors of healthy adults, using fNIRS as the primary assessment modality.
Methods:
In a randomized crossover design, 15 right-handed adults received NMES and PMS sessions (separated by ≥48 h). Stimulation intensity was functionally calibrated to elicit a matched, maximal painless wrist dorsiflexion. Corticospinal excitability was assessed via motor evoked potentials (MEPs) before and after each intervention. Real-time cortical hemodynamics were monitored with functional near-infrared spectroscopy (fNIRS) during stimulation, quantifying changes in oxygenated ([HbO]) and deoxygenated ([HbR]) hemoglobin concentrations across the sensorimotor (SMC), prefrontal (PFC), and occipital (OC) cortices.
Results:
Neither NMES nor PMS induced significant changes in MEP amplitude (NMES: p = 0.674; PMS: p = 0.794). However, fNIRS revealed fundamentally distinct cortical activation patterns during stimulation. NMES was associated with widespread decreases in [HbO] within the PFC, ipsilateral SMC, and OC (p < 0.05). In contrast, PMS elicited focal activation in the contralateral SMC, characterized by a significant increase in [HbO] (ch23: p = 0.005; ch35: p = 0.022) and a concurrent decrease in [HbR] (p < 0.05) compared to the NMES condition. General linear model analysis confirmed more robust contralateral SMC activation during PMS. No significant differences in task-based functional connectivity were observed between the two modalities.
Conclusions:
A single session of NMES and PMS differentially modulates real-time cortical hemodynamics without altering corticospinal excitability. PMS induces focal, excitatory-dominant activation of the contralateral SMC, while NMES evokes a pattern of widespread cortical modulation, reflecting their distinct afferent mechanisms.
