Modulation of cerebellar excitability by polarity-specific noninvasive direct current stimulation.
Modulation of cerebellar excitability by polarity-specific noninvasive direct current stimulation.
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DOI：
10.1523/jneurosci.2184-09.2009
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发表时间：
2009-07-15
期刊：
影响因子：
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通讯作者：
Celnik P
中科院分区：
文献类型：
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作者：
Galea JM;Jayaram G;Ajagbe L;Celnik P
小脑是参与运动控制和认知加工的重要结构。对小脑的非侵入性刺激会导致神经生理和行为的改变，这种影响被归因于小脑-大脑连接的调节。在休息时，小脑对初级运动皮质(M1)施加整体抑制音，即小脑抑制(CBI)，可能是通过齿状-丘脑-皮质连接。然而，这一通路在刺激小脑前后的兴奋性水平尚未被直接研究。在这项研究中，我们使用经颅磁刺激(TMS)来测定在右侧小脑皮质上施加阳极、阴极或假的直流电刺激(TDC)25分钟前后M1、脑干和CBI的变化。我们假设，相对于假刺激，阳极tdcs会导致CBI的增强，而阴极会降低CBI。我们发现，在假刺激后无明显变化的情况下，阴极型tDCs可使CBI明显降低，而阴极型tDCs可使CBI增加。这些效应仅限于小脑-大脑皮层连接，其他M1或脑干兴奋性指标没有变化。对CBI的阴极效应依赖于刺激强度，并可持续到停止tDCS30分钟。这些结果表明，tDCs可以通过改变浦肯野细胞的活动来调节小脑的兴奋性，这种方式可能是局部的和极性的。因此，对小脑的直流电刺激可能对小脑功能障碍患者以及运动控制研究具有重要的潜在意义。
The cerebellum is a crucial structure involved in movement control and cognitive processing. Non-invasive stimulation of the cerebellum results in neurophysiological and behavioral changes, an effect that has been attributed to modulation of cerebello–brain connectivity. At rest, the cerebellum exerts an overall inhibitory tone over the primary motor cortex (M1), cerebello-brain inhibition (CBI), likely through dentate-thalamo-cortical connections. The level of excitability of this pathway before and after stimulation of the cerebellum, however, has not been directly investigated. In this study we used transcranial magnetic stimulation (TMS) to determine changes in M1, brainstem and CBI before and after 25 minutes of anodal, cathodal or sham transcranial direct current stimulation (tDCS) applied over the right cerebellar cortex. We hypothesized that anodal tDCS would result in an enhancement of CBI and cathodal would decrease it, relative to sham stimulation. We found that cathodal tDCS resulted in a clear decrease of CBI, whereas anodal tDCS increased it, in the absence of changes after sham stimulation. These effects were specific to the cerebello-cortical connections with no changes in other M1 or brainstem excitability measures. The cathodal effect on CBI was found to be dependent on stimulation intensity and lasted up to 30 minutes after the cessation of tDCS. These results suggest that tDCS can modulate in a focal and polarity-specific manner cerebellar excitability, likely through changes in Purkinje cell activity. Therefore, direct current stimulation of the cerebellum may have significant potential implications for patients with cerebellar dysfunction as well as to motor control studies.