An increasing number of studies using human subjects substantiate the use of transcranial direct current stimulation (tDCS) as a noninvasive approach to treat various neurological symptoms. tDCS has been tested in conditions from motor to cognition dysfunctions. Performance enhancement of healthy subjects using tDCS has also been explored. The underlying physiological mechanism for tDCS effects is hypothesized to be through changes in neuroplasticity and we have previously demonstrated that in vivo anodal tDCS can enhance neuroplasticity of hippocampal CA1 neurons. The purpose of this study was to determine whether the underlying electrophysiological changes that occur following in vivo tDCS are polarity specific. We also examined both the CA1 and CA3 regions of the hippocampus to determine whether the tDCS effects were subfield specific. We conducted in vivo tests of cathodal tDCS versus anodal tDCS on synaptic plasticity of CA1 and CA3 neurons of male rats. In each region we assessed long term potentiation (LTP), paired pulse facilitation (PPF) and long term depression (LTD). In the CA1 region, we found anodal tDCS significantly enhanced not only LTP and PPF, but also LTD. There was no statistical difference in LTP, PPF or LTD of hippocampal CA1 neurons resulting from cathodal tDCS. Neither anodal nor cathodal tDCS induced significant changes in neuroplasticity of hippocampal CA3 neurons. Results indicate that the effects of tDCS are subfield specific and polarity dependent with anodal tDCS having greater impact on synaptic activity in the rat hippocampus than cathodal tDCS.

中文翻译：

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经颅直流电刺激对海马可塑性的极性和子领域的具体影响。

越来越多的使用人类受试者的研究证实了经颅直流电刺激（tDCS）作为治疗各种神经系统症状的非侵入性方法的用途。tDCS已在从运动到认知功能障碍的条件下进行了测试。还研究了使用tDCS增强健康受试者的表现。据推测，tDCS效应的潜在生理机制是通过神经可塑性的变化而实现的，我们先前已经证明了体内阳极tDCS可以增强海马CA1神经元的神经可塑性。这项研究的目的是确定体内tDCS之后发生的潜在电生理变化是否是极性特异性的。我们还检查了海马的CA1和CA3区域，以确定tDCS的作用是否是子域特异性的。我们对雄性大鼠CA1和CA3神经元的突触可塑性进行了阴极tDCS与阳极tDCS的体内测试。在每个地区，我们评估了长期增强（LTP），配对脉冲促进（PPF）和长期抑郁（LTD）。在CA1区，我们发现阳极tDCS不仅显着增强了LTP和PPF，还显着增强了LTD。阴极tDCS引起的海马CA1神经元的LTP，PPF或LTD无统计学差异。阳极或阴极tDCS均未引起海马CA3神经元神经可塑性的显着变化。结果表明，tDCS的作用是亚域特异性的，且极性取决于阳极的tDCS，其对大鼠海马突触活性的影响要大于阴极的tDCS。