Jones Aaron P, Goncalves-Garcia Monica, Gibson Benjamin, Trumbo Michael C S, Coffman Brian A, Robert Bradley, Gill Hope A, Mullins Teagan, Hunter Michael A, Robinson Charles S H, Combs Angela, Khadka Niranjan, Bikson Marom, Clark Vincent P
Psychology Clinical Neuroscience Center, The University of New Mexico, Albuquerque, NM, USA.
Department of Psychology, The University of New Mexico, Albuquerque, NM, USA.
Neuroimage Rep. 2021 Sep 6;1(4):100048. doi: 10.1016/j.ynirp.2021.100048. eCollection 2021 Dec.
Transcranial direct current stimulation (tDCS) influences performance in many cognitive domains. However, the question of which brain networks are involved in these effects is rarely examined. In prior experiments we identified tDCS protocols that produce a large improvement in category learning. Here we examined which brain regions were involved by modelling and comparing the behavioral effects of different electrode placements. In Experiment 1, we placed electrodes at two cephalic sites found the be most effective in our prior studies (F10 and T5/P7), expecting an increased combined effect. However, no effect was found, suggesting that stimulation of additional far field regions using extracephalic electrodes in our prior studies may have been necessary for producing these effects. In Experiment 2, we used finite element modeling (FEM) to compare the E-fields produced by these montages. One region with large differences and that is accessible to tDCS was the cerebellum. We then tested the involvement of the cerebellum by placing electrodes below the inion vs. the left arm in thirty-six participants who received anodal, cathodal, or sham stimulation during training. Neither anodal nor cathodal cerebellar tDCS led to significant changes when compared with sham. These results suggest that neither far-field stimulation of the cerebellum nor nearby cranial nerves played a large causal role in our previous tDCS studies. To our knowledge, this one of the first studies to systematically compare the behavioral and energetic effects produced by different montages to identify the specific brain regions involved in the behavioral responses to tDCS.
经颅直流电刺激（tDCS）会影响许多认知领域的表现。然而，很少有人研究这些效应涉及哪些脑网络。在之前的实验中，我们确定了能在类别学习方面带来显著改善的tDCS方案。在此，我们通过对不同电极放置的行为效应进行建模和比较，来研究哪些脑区参与其中。在实验1中，我们将电极置于两个在之前研究中发现最有效的头部位置（F10和T5/P7），期望能增强联合效应。然而，未发现任何效果，这表明在我们之前的研究中，使用头皮外电极刺激额外的远场区域可能对产生这些效应是必要的。在实验2中，我们使用有限元模型（FEM）来比较这些电极组合产生的电场。一个差异较大且tDCS可作用的区域是小脑。然后，我们在36名参与者训练期间，通过将电极置于枕外隆凸下方与置于左臂进行比较，来测试小脑的参与情况，这些参与者接受了阳极、阴极或假刺激。与假刺激相比，阳极和阴极小脑tDCS均未导致显著变化。这些结果表明，在我们之前的tDCS研究中，小脑的远场刺激和附近的颅神经均未起到很大的因果作用。据我们所知，这是首批系统比较不同电极组合产生的行为和能量效应，以确定参与tDCS行为反应的特定脑区的研究之一。
