Efficacy of slow oscillatory-transcranial direct current stimulation on EEG and memory - contribution of an inter-individual factor
Efficacy of slow oscillatory-transcranial direct current stimulation on EEG and memory - contribution of an inter-individual factor
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DOI：
10.1111/ejn.13877
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发表时间：
2018-04-01
影响因子：
3.4
通讯作者：
Marshall, Lisa
中科院分区：
文献类型：
--
作者：
Koo, Ping Chai;Moelle, Matthias;Marshall, Lisa
尽管有许多关于非快速眼动（NREM）睡眠期间的阳极慢振荡经颅直流电刺激（so-tDCS）对记忆巩固有益的报道，但也经常观察到负面结果。我们的工作假设是，so-tDCS的功效强烈依赖于潜在网络的易感性。一个决定网络易感性的因素被假设反映在学习或任务诱导的“可塑性变化”中。另一个成分被假设为代表个体间的混淆。25名（15名女）健康学生在夜间早期NREM睡眠中参加了有和没有so-tDCS的两种学习条件，并在没有学习任务的一种对照条件下参加了学习任务。So-tDCS分5个5分钟时段应用。脑电图在两个时间窗内进行评估：急性期（每次刺激阻断后5个1分钟epoch）和刺激后150分钟时间段。通过记忆商（MQ）评估个体间差异，并将受试者分为高分组和低分组。尽管so-tDCS在150 min内对快速主轴参数均有增强作用，但对记忆巩固无调节作用。相比之下，在MQ高的受试者中，在so-tDCS后，对图形配对联想任务的记忆保留显著增加。任务诱发的慢纺锤体密度在高MQ组与低MQ组中呈相反方向调制，仅在高MQ组中增加。so-tDCS对脑电的影响仅限于两个时间窗内的快速纺轴调制。这些结果表明，个体间的混淆会影响so-tDCS的疗效，提示这些因素作为生物标志物的潜在用途。
Despite many reports on beneficial effects of anodal slow oscillatory-transcranial direct current stimulation (so-tDCS) during non-rapid eye movement (NREM) sleep on memory consolidation, frequent negative outcomes have also been observed. Our working hypothesis is that so-tDCS efficacy is strongly dependent upon the susceptibility of the underlying network. One component determining susceptibility of the network is hypothesized to be reflected in learning or task-induced' plastic changes. Another component is hypothesized to represent inter-individual confounds. Twenty-five (15 female) healthy students participated in two learning conditions with and without so-tDCS during early nocturnal NREM sleep and in one control condition without learning tasks. So-tDCS was applied in five 5-min blocks. EEG was assessed during two time windows: an acute period with five 1-min epochs after each stimulation block and a 150-min post-stimulation time period. Inter-individual differences were assessed by a memory quotient (MQ) and subjects classified into high- vs. low-scoring groups. Although so-tDCS was efficient in enhancing fast spindle parameters in the 150-min time period in all subjects, so-tDCS failed to modulate memory consolidation. In contrast, in subjects with a high MQ, memory retention on a figural paired-associate task was significantly increased after so-tDCS. Task-induced slow spindle density was modulated in the opposite direction in subjects with high vs. low MQ being increased in the high-MQ group only. Effects of so-tDCS on EEG were limited to fast spindle modulations in both time windows. These results reveal that inter-individual confound can impact so-tDCS efficacy, suggesting potential use of such factors as biomarkers.