Thom Jude L, Staresina Bernhard P
Department of Experimental Psychology, University of Oxford, Oxford, UK.
Oxford Centre for Human Brain Activity, Wellcome Centre for Integrative Neuroimaging, Department of Psychiatry, University of Oxford, Oxford, UK.
Sleep. 2025 Jul 11;48(7). doi: 10.1093/sleep/zsaf114.
Spindles are hallmark oscillations during non-rapid-eye-movement (NREM) sleep. Together with slow oscillations (SOs), they are thought to play a mechanistic role in the consolidation of learned information. The quantity and spatial distribution of spindles have been linked to brain activity during learning before sleep and to memory performance after sleep. If spindles are drawn to cortical areas excited through pre-sleep learning tasks, this begs the question of whether the spatial distribution of spindles is flexible, and whether their regional expression can also be manipulated with experimental brain stimulation. We used excitatory transcranial direct current stimulation (tDCS) to stimulate the left and right motor cortex in a repeated-measures experimental design. After stimulation, we recorded high-density electroencephalography (EEG) during sleep to test how local stimulation modulated the regional expression of sleep spindles. Indeed, we show that excitatory tDCS of local cortical sites before sleep biases the expression of spindles to the excited locations during subsequent sleep. No effects of localized tDCS excitation were seen for SOs. These results demonstrate that the spatial topography of sleep spindles is neither hard-wired nor random, with spindles being flexibly directed to exogenously excited cortical circuits.
纺锤波是非快速眼动（NREM）睡眠期间的标志性振荡。与慢波振荡（SOs）一起，它们被认为在学习信息巩固过程中发挥着机制性作用。纺锤波的数量和空间分布与睡眠前学习期间的大脑活动以及睡眠后的记忆表现有关。如果纺锤波被吸引到通过睡眠前学习任务而兴奋的皮质区域，这就引出了一个问题：纺锤波的空间分布是否具有灵活性，以及它们在区域的表现是否也可以通过实验性脑刺激来操控。我们采用兴奋性经颅直流电刺激（tDCS），在重复测量实验设计中刺激左右运动皮质。刺激后，我们在睡眠期间记录高密度脑电图（EEG），以测试局部刺激如何调节睡眠纺锤波的区域表现。事实上，我们发现睡眠前对局部皮质部位进行兴奋性tDCS会使后续睡眠期间纺锤波的表现偏向于兴奋部位。局部tDCS刺激对慢波振荡没有影响。这些结果表明，睡眠纺锤波的空间拓扑结构既不是固定不变的，也不是随机的，纺锤波会灵活地导向外源性兴奋的皮质回路。
