Cross-hemispheric Alternating Current Stimulation During a Nap Disrupts Slow Wave Activity and Associated Memory Consolidation.
Cross-hemispheric Alternating Current Stimulation During a Nap Disrupts Slow Wave Activity and Associated Memory Consolidation.
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DOI：
10.1016/j.brs.2014.12.010
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发表时间：
2015-05
影响因子：
7.7
通讯作者：
Walsh V
中科院分区：
文献类型：
--
作者：
Garside P;Arizpe J;Lau CI;Goh C;Walsh V
慢波活动(SWA)是一种以慢波睡眠(SWS)为特征的低频振荡，被认为与夜间睡眠中陈述性记忆巩固有关。然而，将SWA与午睡期间的记忆巩固联系起来的证据是相互矛盾的。我们应用了经颅交流电刺激(Tacs)--它带有跨半球电极蒙太奇(F3和F4-International 10：20 EEG系统)，能够扰乱大脑振荡--以确定午睡期间低频振荡产生的中断是否与陈述性记忆巩固的中断有因果关系。八名人类受试者每人都参加了刺激和假午睡。言语配对联想学习(PAL)任务测量记忆变化。在每次午睡期间，给予5次5min的刺激(0.75赫兹的跨半球额叶TAC)或假刺激间隔，刺激后间隔为1min。在刺激开始前的1分钟和刺激开始的1分钟内，我们分析了慢速(0.7兆赫兹)、德尔塔(1.0兆赫兹)、西塔频率(4.0兆赫兹)、阿尔法频率(8.0兆赫兹)和主轴范围频率(12.0兆赫兹)的频谱脑电功率。正如假设的那样，刺激导致的能量减少与打盹后单词对回忆的减少呈正相关，尤其是慢(P<0.0022)和D(P<0.0022；(0.037)个频段。这些结果提供了初步证据，表明SWA在NAP期间的陈述性记忆巩固中起着因果和特定的作用。跨半球Tacs干扰了午睡时低频振荡的产生。振荡性干扰与陈述性记忆巩固干扰相关。缺乏刺激、低频振荡也与固结相关。刺激29min后，低频振荡出现回升。提出了低频率振荡在小睡期间固结中的原因作用。
Slow Wave Activity (SWA), the low frequency (<4 Hz) oscillations that characterize Slow Wave Sleep (SWS) are thought to relate causally to declarative memory consolidation during nocturnal sleep. Evidence is conflicting relating SWA to memory consolidation during nap however. We applied transcranial alternating current stimulation (tACS) – which, with a cross-hemispheric electrode montage (F3 and F4 – International 10:20 EEG system), is able to disrupt brain oscillations–to determine if disruption of low frequency oscillation generation during afternoon nap is causally related to disruption in declarative memory consolidation. Eight human subjects each participated in stimulation and sham nap sessions. A verbal paired associate learning (PAL) task measured memory changes. During each nap period, five 5-min stimulation (0.75 Hz cross-hemispheric frontal tACS) or sham intervals were applied with 1-min post-stimulation intervals (PSI's). Spectral EEG power for Slow (0.7–0.8 Hz), Delta (1.0–4.0 Hz), Theta (4.0–8.0 Hz), Alpha (8.0–12.0 Hz), and Spindle-range (12.0–14.0) frequencies was analyzed during the 1-min preceding the onset of stimulation and the 1-min PSI's. As hypothesized, power reduction due to stimulation positively correlated with reduction in word-pair recall post-nap specifically for Slow (P < 0.0022) and Delta (P < 0.037) frequency bands. These results provide preliminary evidence suggesting a causal and specific role of SWA in declarative memory consolidation during nap. Cross-hemispheric tACS disrupted low frequency oscillation generation in afternoon nap. Oscillation disruption correlated with declarative memory consolidation disruption. Absent stimulation, low frequency oscillations also correlated with consolidation. A rebound in low frequency oscillations was observed after 29 min of stimulation. A causal role of low frequency oscillations in consolidation during nap is suggested.