Frontal Cortex Activation During Electrical Muscle Stimulation as Revealed by Functional Near-Infrared Spectroscopy

摘要

Electrical muscle stimulation (EMS) is a widely applied technique in clinical medicine and sports training to generate muscle contractions by activating peripheral motor axons [7]. Although less well studied, EMS can also activate peripheral sensory axons that send proprioceptive and pain signals from the muscle to the sensory, motor, and association cortices, thereby increasing cortical excitability and activation [1, 2, 6]. For example, Blickenstorfer et al. [1] used fMRI to measure cortical and subcortical activation responses during EMS of the wrist extensors/flexors, and showed an activation pattern comprising the contralateral primary motor and somatosensory cortex, and premotor cortex; the ipsilateral cerebellum; bilateral secondary somatosensory cortex, the supplementary motor area, and anterior cingulate cortex. Moreover, Smith et al. [6] showed a relationship between changes in senso-rimotor cortical activation using fMRI and increased current intensity during EMS of the knee extensors, which the authors presumed was related to pain processing.