Transcranial direct current stimulation (tDCS) is a noninvasive technique for modulating neural plasticity and is considered to have therapeutic potential in neurological disorders. For the purpose of translational neuroscience research, a suitable animal model can be ideal for providing a stable condition for identifying mechanisms that can help to explore therapeutic strategies. Here, we developed a tDCS protocol for modulating motor excitability in anesthetized rats. To examine the responses of tDCS-elicited plasticity, the motor evoked potential (MEP) and MEP input-output (IO) curve elicited by epidural motor cortical electrical stimulus were evaluated at baseline and after 30 min of anodal tDCS or cathodal tDCS. Furthermore, a paired-pulse cortical electrical stimulus was applied to assess changes in the inhibitory network by measuring long-interval intracortical inhibition (LICI) before and after tDCS. In the results, analogous to those observed in humans, the present study demonstrates long-term potentiation- (LTP-) and long-term depression- (LTD-) like plasticity can be induced by tDCS protocol in anesthetized rats. We found that the MEPs were significantly enhanced immediately after anodal tDCS at 0.1 mA and 0.8 mA and remained enhanced for 30 min. Similarly, MEPs were suppressed immediately after cathodal tDCS at 0.8 mA and lasted for 30 min. No effect was noted on the MEP magnitude under sham tDCS stimulation. Furthermore, the IO curve slope was elevated following anodal tDCS and presented a trend toward diminished slope after cathodal tDCS. No significant differences in the LICI ratio of pre- to post-tDCS were observed. These results indicated that developed tDCS schemes can produce consistent, rapid, and controllable electrophysiological changes in corticomotor excitability in rats. This newly developed tDCS animal model could be useful to further explore mechanical insights and may serve as a translational platform bridging human and animal studies, establishing new therapeutic strategies for neurological disorders.

中文翻译：

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经颅直流电刺激对大鼠运动兴奋性的神经调节作用。


经颅直流电刺激（tDCS）是一种调节神经可塑性的无创技术，被认为具有治疗神经系统疾病的潜力。出于转化神经科学研究的目的，合适的动物模型非常适合提供稳定的条件，以识别有助于探索治疗策略的机制。在这里，我们开发了一种用于调节麻醉大鼠运动兴奋性的 tDCS 方案。为了检查 tDCS 引起的可塑性反应，在基线和阳极 tDCS 或阴极 tDCS 30 分钟后评估硬膜外运动皮质电刺激引起的运动诱发电位 (MEP) 和 MEP 输入输出 (IO) 曲线。此外，通过测量 tDCS 前后的长间隔皮质内抑制 (LICI)，应用配对脉冲皮质电刺激来评估抑制网络的变化。结果与在人类中观察到的结果类似，本研究表明 tDCS 方案可以在麻醉大鼠中诱导长时程增强 (LTP-) 和长时程抑制 (LTD-) 样可塑性。我们发现，在 0.1 mA 和 0.8 mA 的阳极 tDCS 后，MEP 立即显着增强，并保持增强 30 分钟。同样，MEP 在 0.8 mA 阴极 tDCS 后立即受到抑制，并持续 30 分钟。在假 tDCS 刺激下，未观察到对 MEP 幅度的影响。此外，阳极 tDCS 后 IO 曲线斜率升高，阴极 tDCS 后呈现斜率减小的趋势。 tDCS 前后的 LICI 比率没有观察到显着差异。 这些结果表明，开发的 tDCS 方案可以对大鼠皮质运动兴奋性产生一致、快速且可控的电生理变化。这种新开发的 tDCS 动物模型可用于进一步探索机械见解，并可作为连接人类和动物研究的转化平台，为神经系统疾病建立新的治疗策略。