Hordacre Brenton, Moezzi Bahar, Goldsworthy Mitchell R, Rogasch Nigel C, Graetz Lynton J, Ridding Michael C
The Robinson Research Institute, School of Medicine, The University of Adelaide, Adelaide, 5005, SA, Australia.
Computational and Theoretical Neuroscience Laboratory, School of Information Technology and Mathematical Sciences, University of South Australia, Mawson Lakes, SA, Australia.
Eur J Neurosci. 2017 Mar;45(6):837-845. doi: 10.1111/ejn.13508. Epub 2017 Jan 18.
Responses to non-invasive brain stimulation are highly variable between subjects. Resting state functional connectivity was investigated as a marker of plasticity induced by anodal transcranial direct current stimulation (tDCS). Twenty-six healthy adults (15 male, 26.4 ± 6.5 years) were tested. Experiment 1 investigated whether functional connectivity could predict modulation of corticospinal excitability following anodal tDCS. Experiment 2 determined test-retest reliability of connectivity measures. Three minutes of electroencephalography was recorded and connectivity was quantified with the debiased weighted phase lag index. Anodal (1 mA, 20 min) or sham tDCS was applied to the left primary motor cortex (M1), with a change in motor evoked potential amplitude recorded from the right first dorsal interosseous used as a marker of tDCS response. Connectivity in the high beta frequency (20-30 Hz) between an electrode approximating the left M1 (C3) and electrodes overlying the left parietal cortex was a strong predictor of tDCS response (cross-validated R = 0.69). Similar relationships were observed for alpha (8-13 Hz; R = 0.64), theta (4-7 Hz; R = 0.53), and low beta (14-19 Hz; R = 0.58) frequencies, however, test-retest reliability of connectivity measures was strongest for the high beta frequency model (ICC = 0.65; good reliability). Further investigation of the high beta model found that greater connectivity between C3 and a cluster of electrodes approximately overlying the left parietal cortex was associated with stronger responses to anodal (rho = 0.61, P = 0.03), but not sham tDCS (rho = 0.43, P = 0.14). Functional connectivity is a strong predictor of the neuroplastic response to tDCS and may be one important characteristic to assist targeted tDCS application.
不同受试者对非侵入性脑刺激的反应差异很大。静息态功能连接性被作为阳极经颅直流电刺激（tDCS）诱导可塑性的一个标志物进行研究。对26名健康成年人（15名男性，年龄26.4±6.5岁）进行了测试。实验1研究功能连接性是否能够预测阳极tDCS后皮质脊髓兴奋性的调制。实验2确定连接性测量的重测信度。记录3分钟脑电图，并使用去偏加权相位滞后指数对连接性进行量化。将阳极（1毫安，20分钟）或伪tDCS施加于左侧初级运动皮层（M1），记录右侧第一背侧骨间肌运动诱发电位幅度的变化，将其用作tDCS反应的标志物。在接近左侧M1的电极（C3）与左侧顶叶皮层上方的电极之间的高β频率（20 - 30赫兹）连接性是tDCS反应的一个强预测指标（交叉验证R = 0.69）。在α（8 - 13赫兹；R = 0.64）、θ（4 - 7赫兹；R = 0.53）和低β（14 - 19赫兹；R = 0.58）频率下也观察到了类似关系，然而，连接性测量的重测信度在高β频率模型中最强（组内相关系数ICC = 0.65；良好信度）。对高β模型的进一步研究发现，C3与左侧顶叶皮层上方大致覆盖的一组电极之间更强的连接性与对阳极tDCS的更强反应相关（斯皮尔曼相关系数rho = 0.61，P = 0.03），但与伪tDCS无关（rho = 0.43，P = 0.14）。功能连接性是对tDCS神经可塑性反应的一个强预测指标，可能是辅助靶向tDCS应用的一个重要特征。
