| Summary: | 碩士 === 國立成功大學 === 生物醫學工程學系 === 100 === In addition to limb function restoration and neuromodulation, electrical stimulation (ES) has been shown effective in altering cortical plasticity. Recently, increasing interest has been focused on the effect of hybrid stimulation (HS) which incorporates voluntary contraction and ES on brain activity and muscle metabolism. The purpose of present study was to characterize the cortical contribution to the neural control and muscle oxygenation during isometric knee extension task in volitional contraction (VOL), ES, HS schemes. Nighteen male subjects performed one set of isometric knee extension at 30% MVC in five randomized trials of volitional contraction (VOL), electrical stimulation (ES) only, and three hybrid stimulations with 10 mA, 30 mA, and 50 mA intensities, respectively. A frequency-domain near infrared spectroscopy (FD-NIRS) system was employed to assess the cortical activity from the bilateral sensorimotor cortices (SMCs), supplementary motor areas (SMAs), and premotor cortices (PMCs) as well as the muscle oxygenation in the vastus laterali (VL). Our results showed that ES had a similar cortical activation pattern to that during VOL but with smaller intensity. Augmented sensorimotor network was observed during VOL in parallel with ES. In addition, prominent lateralizations of PMC were found in all conditions. Oxygen consumption of muscle was significantly higher in HS-III, HS-II and ES when compared to VOL, implying that the intervention of ES accelerates the oxygen saturation depletion during muscle contraction. These results suggest that HS not only can enhance the activation of cortical regions but also facilitate muscle metabolism.
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