OBJECTIVE Transcranial near-infrared stimulation (tNIRS) can penetrate the scalp and skull and can reach the superficial layers of the cerebral cortex. In this study, we evaluated whether an 820-nm tNIRS can modulate the excitability of the primary motor cortex (M1) as measured by transcranial magnetic stimulation (TMS). METHODS tNIRS was applied at a wavelength of 820-nm for 4 min over the representation of the right first dorsal interosseous muscle (FDI) in the left M1, in 12 healthy right-handed participants. Motor evoked potentials (MEPs) from the FDI elicited by single-pulse TMS were measured at baseline and up to 30 min after the tNIRS. RESULTS The ΔMEPs percentage was evaluated, and a significant increase in amplitude was observed 10-20 min post-stimulation compared to that in sham. CONCLUSION This study provides evidence that an 820-nm tNIRS induces transitory increase in the excitability of the stimulated cortex.

中文翻译：

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经颅近红外刺激可能会增加人类记录的皮层兴奋性。

目的经颅近红外刺激（tNIRS）可以穿透头皮和颅骨，并可以到达大脑皮层的浅层。在这项研究中，我们评估了820 nm tNIRS是否可以通过经颅磁刺激（TMS）来调节初级运动皮层（M1）的兴奋性。方法在12位健康的惯用右手参与者中，将tNIRS在820 nm波长处施加于左M1的右第一背骨间肌（FDI）的图示上，持续4分钟。在基线和tNIRS后最多30分钟内，测量由单脉冲TMS引起的FDI产生的运动诱发电位（MEP）。结果评估了ΔMEPs百分比，与假手术相比，在刺激后10-20分钟观察到振幅显着增加。