Modulating parameters of excitability during and after transcranial direct current stimulation of the human motor cortex
Modulating parameters of excitability during and after transcranial direct current stimulation of the human motor cortex
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DOI：
10.1113/jphysiol.2005.092429
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发表时间：
2005-10-01
影响因子：
5.5
通讯作者：
Tergau, F
中科院分区：
文献类型：
--
作者：
Nitsche, MA;Seeber, A;Tergau, F
弱经颅直流电刺激（tDCS）的人类运动皮层的兴奋性发生变化的过程中和刺激后。这些兴奋性的转变是极性特异性的，阳极tDCS增强兴奋性，阴极降低it. To探索这种兴奋性调制的起源更详细，我们测量了输入-输出曲线和运动阈值的皮质脊髓兴奋性的全局参数，并确定皮质内抑制和促进，以及易化间接波（I波）的相互作用。在短期tDCS期间进行测量，这不会引起后遗症，并且在其他tDCS方案期间进行测量，这些方案会引起短期和长期后遗症。静息和活动运动阈值在tDCS期间和之后保持稳定。输入-输出曲线的斜率由阳极tDCS增加，由阴极tDCS降低。初级运动皮层的阳极tDCS减少了tDCS后的皮层内抑制和增强了促进作用，但在tDCS期间没有。阴极tDCS在给药期间减少了易化，并在给药后增加了抑制。在tDCS期间，I波易化不受影响，但对于后效，阳极tDCS增加I波易化，而阴极tDCS仅具有轻微影响。这些结果表明，tDCS对皮质脊髓兴奋性的影响，在短期内的刺激（不诱导后效）主要取决于阈下静息膜电位的变化，这是能够调节的输入-输出曲线，但不是运动阈值。相反，tDCS的后效是由于皮质内抑制和易化的变化，至少部分也是由于易化I波相互作用，这是由突触活动控制。
Weak transcranial direct current stimulation (tDCS) of the human motor cortex results in excitability shifts which occur during and after stimulation. These excitability shifts are polarity-specific with anodal tDCS enhancing excitability, and cathodal reducing it. To explore the origin of this excitability modulation in more detail, we measured the input-output curve and motor thresholds as global parameters of cortico-spinal excitability and determined intracortical inhibition and facilitation, as well as facilitatory indirect wave (I-wave) interactions. Measurements were performed during short-term tDCS, which elicits no after-effects, and during other tDCS protocols which do elicit short- and long-lasting after-effects. Resting and active motor thresholds remained stable during and after tDCS. The slope of the input-output curve was increased by anodal tDCS and decreased by cathodal tDCS. Anodal tDCS of the primary motor cortex reduced intracortical inhibition and enhanced facilitation after tDCS but not during tDCS. Cathodal tDCS reduced facilitation during, and additionally increased inhibition after its administration. During tDCS, I-wave facilitation was not influenced but, for the after-effects, anodal tDCS increased I-wave facilitation, while cathodal tDCS had only minor effects. These results suggest that the effect of tDCS on cortico-spinal excitability during a short period of stimulation (which does not induce after-effects) primarily depends on subthreshold resting membrane potential changes, which are able to modulate the input-output curve, but not motor thresholds. In contrast, the after-effects of tDCS are due to shifts in intracortical inhibition and facilitation, and at least partly also to facilitatory I-wave interaction, which is controlled by synaptic activity.