Evaluation of acute anodal direct current stimulation-induced effects on somatosensory-evoked responses in the rat
Evaluation of acute anodal direct current stimulation-induced effects on somatosensory-evoked responses in the rat
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DOI：
10.1016/j.brainres.2019.146318
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发表时间：
2019-10
期刊：
影响因子：
2.9
通讯作者：
Nobuo Kunori;I. Takashima
中科院分区：
文献类型：
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作者：
Nobuo Kunori;I. Takashima
经颅直流电刺激（tDCS）是一种用于治疗脑部疾病的非侵入性工具。DC电场被认为调节神经元兴奋性，并且据报道其在电极下方的局部治疗区域内以及在延伸超出电极的扩散脑区域中发挥作用。然而，tDCS影响皮层神经传递和调节远端相互连接的皮层区域神经活动的方式仍不清楚。因此，本研究探讨了阳极DCS（aDCS）对前肢诱发的感觉反应，最初出现在初级感觉运动皮层（S1-M1），然后传播到次级运动皮层（M2）的影响。当aDCS应用仅限于S1-M1区域时，局部场电位（LFP）记录和电压敏感染料（VSD）成像显示，S1-M1的前肢诱发反应明显增强。相比之下，M2的神经反应几乎保持不变。另一方面，仅限于M2的aDCS应用增加了M2的前肢诱发反应，而不是S1-M1。两者合计，这些结果表明，当应用于皮层时，aDCS可能具有内在的局部效应，直接影响刺激部位下方的传入神经活动。因此，目前的结果表明，aDCS有较小的影响，在遥远的皮层区域互连的刺激部位比在刺激部位本身的神经活动。因此，研究结果不支持DCS通过皮质-皮质连接远程激活的想法，至少在大鼠的S1-M1和M2区域之间。
Transcranial direct current stimulation (tDCS) is a non-invasive tool used to treat brain disorders. The DC electric field is thought to modulate neuronal excitability and it has been reported to exert effects within the localized treatment area under the electrode, as well as in diffuse brain regions extending beyond the electrode. However, the manner in which tDCS influences neural transmission in the cortex and modulates neural activity in distant interconnected cortical regions remains unclear. Thus, the present study investigated the effects of anodal DCS (aDCS) on the forelimb-evoked sensory response that initially appears in the primary sensorimotor cortex (S1-M1) and then propagates to the secondary motor cortex (M2). When aDCS application was confined to the S1-M1 region, local field potential (LFP) recordings and voltage-sensitive dye (VSD) imaging revealed that the forelimb-evoked response in the S1-M1 was clearly enhanced. In contrast, the neural response in the M2 remained almost unchanged. On the other hand, aDCS application confined to the M2 increased the forelimb-evoked response in the M2 but not the S1-M1. Taken together, these results suggest that, when applied to the cortex, the aDCS may have intrinsic local effects, influencing afferent neural activity immediately underneath the stimulation site. Thus, the present results indicate that aDCS has less influence on neural activity in distant cortical areas interconnected to the stimulation site than at the stimulation site itself. Therefore, the findings do not support the idea of DCS remote activation via cortico-cortical connections, at least between the S1-M1 and M2 regions in rats.