经颅交流电刺激(tACS)是一种通过在头皮施加微弱交流电刺激、从而进行神经调节的非侵入刺激技术,已经被证实可以调节大脑的认知功能.心理旋转是一种想像客体或自身旋转的空间表征转换能力,是衡量空间认知能力的重要标尺之一.探索tACS对心理旋转认知能力的影响,利用心理旋转实验范式,以行为学表现和ERP、ERD等电生理参数作为主要评判指标,分析tACS对心理旋转产生的作用.行为学结果表明,alpha节律的tACS可以显著减少反映时间(P＜0.05),并且反映时随着刺激图片旋转角度的增加先增大后减小.比较对照组和8 ～12 Hz刺激组的心理旋转相关的负波(RRN),发现刺激组的RRN幅值比对照组幅值低(刺激组vs对照组,P＜0.05),同时发现RRN幅值随着刺激图片旋转角度的增加呈现先降低后升高的趋势.时频分析结果显示,刺激组的alpha和beta频段的事件相关去同步(ERD)现象比对照组更弱(刺激组vs对照组,JP＜0.05),且ERD开始时间更早.有研究表明,ERD强弱与大脑激活水平有关,说明tACS作用后,大脑激活水平降低;进而提示tACS可以提高被试的心理旋转能力,有望成为提高空间认知能力的新途径.%Transcranial alternating current stimulation (tACS) is a new non-invasive technology that applies weak electrical stimulation on the scalp to regulate neural activity.It has been confirmed that tACS can regulate spontaneous brain rhythm and influence cognitive process.Mental rotation is an important benchmark to measure spatial cognitive ability by imaging rotate object or itself.This study used mental rotation experimental paradigm to explore the effects of tACS on the mental rotation cognitive,the main evaluation indexes were behavioral performance and electrophysiological parameters like event related potential (ERP) and event related desynchronization (ERD).Behavioral results showed that the alpha tACS significantly reduced the reaction time(P ＜ 0.05),and with the image rotation angle increasing,the reaction time increased first and then decreased.Compared the mental rotation related negative wave between control group and stimulation group,we found that the RRN amplitude of stimulation group was lower than that of control group (stim vs sham,P ＜ 0.05),and it decreased first and then increased with the rotation angel increasing.The time-frequency analysis showed that the event related desynchronization in alpha and beta bands of stimulation group was weaker than that of control group (stim vs sham,P ＜ 0.05),and it appeared earlier than that of control group,indicating that tACS reduced the level of brain activation based on the earlier results that ERD is related to brain activation level.These results implied that tACS could improve the mental rotation ability and was potential in becoming a new way to improve the spatial cognitive ability.
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