Department of Psychiatry, University of Wisconsin-Madison, Madison, Wisconsin 53719, USA.
J Neurosci. 2011 Dec 7;31(49):17821-34. doi: 10.1523/JNEUROSCI.2604-11.2011.
Sleep spindles are an electroencephalographic (EEG) hallmark of non-rapid eye movement (NREM) sleep and are believed to mediate many sleep-related functions, from memory consolidation to cortical development. Spindles differ in location, frequency, and association with slow waves, but whether this heterogeneity may reflect different physiological processes and potentially serve different functional roles remains unclear. Here we used a unique opportunity to record intracranial depth EEG and single-unit activity in multiple brain regions of neurosurgical patients to better characterize spindle activity in human sleep. We find that spindles occur across multiple neocortical regions, and less frequently also in the parahippocampal gyrus and hippocampus. Most spindles are spatially restricted to specific brain regions. In addition, spindle frequency is topographically organized with a sharp transition around the supplementary motor area between fast (13-15 Hz) centroparietal spindles often occurring with slow-wave up-states, and slow (9-12 Hz) frontal spindles occurring 200 ms later on average. Spindle variability across regions may reflect the underlying thalamocortical projections. We also find that during individual spindles, frequency decreases within and between regions. In addition, deeper NREM sleep is associated with a reduction in spindle occurrence and spindle frequency. Frequency changes between regions, during individual spindles, and across sleep may reflect the same phenomenon, the underlying level of thalamocortical hyperpolarization. Finally, during spindles neuronal firing rates are not consistently modulated, although some neurons exhibit phase-locked discharges. Overall, anatomical considerations can account well for regional spindle characteristics, while variable hyperpolarization levels can explain differences in spindle frequency.
睡眠纺锤波是非快速眼动（NREM）睡眠的脑电图（EEG）标志，被认为介导许多与睡眠相关的功能，从记忆巩固到皮质发育。纺锤波在位置、频率和与慢波的关联上存在差异，但这种异质性是否可能反映不同的生理过程，并可能发挥不同的功能作用尚不清楚。在这里，我们利用记录神经外科患者颅内深度脑电图和多个脑区单个神经元活动的独特机会，更好地描述人类睡眠中的纺锤波活动。我们发现，纺锤波发生在多个新皮质区域，在海马旁回和海马区也较少发生。大多数纺锤波在空间上局限于特定的脑区。此外，纺锤波频率具有地形组织，在补充运动区周围存在明显的转变，快速（13-15 Hz）中央顶叶纺锤波通常与慢波上涌同时发生，而平均晚 200 毫秒的慢速（9-12 Hz）额部纺锤波发生。跨区域的纺锤波变异性可能反映了潜在的丘脑皮质投射。我们还发现，在单个纺锤波期间，频率在区域内和区域间都降低。此外，深度 NREM 睡眠与纺锤波发生和频率降低有关。在单个纺锤波期间和整个睡眠过程中，区域之间的频率变化可能反映了相同的现象，即潜在的丘脑皮质超极化水平。最后，在纺锤波期间，神经元放电率没有一致地调制，尽管一些神经元表现出相位锁定放电。总体而言，解剖学考虑可以很好地解释区域纺锤波特征，而可变的超极化水平可以解释纺锤波频率的差异。
