Gheorghe Delia A, Panouillères Muriel T N, Walsh Nicholas D
School of Psychology, University of East Anglia, Norwich, UK.
Department of Psychiatry, University of Oxford, Oxford, UK.
Cerebellum Ataxias. 2021 Jan 4;8(1):1. doi: 10.1186/s40673-020-00124-y.
Transcranial Direct Current Stimulation (tDCS) over the prefrontal cortex has been shown to modulate subjective, neuronal and neuroendocrine responses, particularly in the context of stress processing. However, it is currently unknown whether tDCS stimulation over other brain regions, such as the cerebellum, can similarly affect the stress response. Despite increasing evidence linking the cerebellum to stress-related processing, no studies have investigated the hormonal and behavioural effects of cerebellar tDCS.
This study tested the hypothesis of a cerebellar tDCS effect on mood, behaviour and cortisol. To do this we employed a single-blind, sham-controlled design to measure performance on a cerebellar-dependent saccadic adaptation task, together with changes in cortisol output and mood, during online anodal and cathodal stimulation. Forty-five participants were included in the analysis. Stimulation groups were matched on demographic variables, potential confounding factors known to affect cortisol levels, mood and a number of personality characteristics.
Results showed that tDCS polarity did not affect cortisol levels or subjective mood, but did affect behaviour. Participants receiving anodal stimulation showed an 8.4% increase in saccadic adaptation, which was significantly larger compared to the cathodal group (1.6%).
The stimulation effect on saccadic adaptation contributes to the current body of literature examining the mechanisms of cerebellar stimulation on associated function. We conclude that further studies are needed to understand whether and how cerebellar tDCS may module stress reactivity under challenge conditions.
经颅直流电刺激（tDCS）作用于前额叶皮层已被证明可调节主观、神经元和神经内分泌反应，尤其是在应激处理的背景下。然而，目前尚不清楚tDCS刺激其他脑区，如小脑，是否能同样影响应激反应。尽管越来越多的证据表明小脑与应激相关处理有关，但尚无研究调查小脑tDCS的激素和行为效应。
本研究测试了小脑tDCS对情绪、行为和皮质醇影响的假设。为此，我们采用单盲、假刺激对照设计，在阳极和阴极在线刺激期间，测量依赖小脑的眼球运动适应性任务的表现，以及皮质醇分泌和情绪的变化。45名参与者纳入分析。刺激组在人口统计学变量、已知影响皮质醇水平、情绪和一些人格特征的潜在混杂因素方面进行了匹配。
结果表明，tDCS的极性不影响皮质醇水平或主观情绪，但会影响行为。接受阳极刺激的参与者眼球运动适应性增加了8.4%，与阴极组（1.6%）相比显著更大。
对眼球运动适应性的刺激效应有助于当前研究小脑刺激对相关功能机制的文献。我们得出结论，需要进一步研究以了解小脑tDCS在挑战条件下是否以及如何调节应激反应性。
