Department of Radiology, University of California at San Diego, La Jolla, California 92093.
Institute of Cognitive Neuroscience and Psychology, Research Center for Natural Sciences, Hungarian Academy of Science, Budapest, Hungary 1117.
J Neurosci. 2018 Mar 21;38(12):3013-3025. doi: 10.1523/JNEUROSCI.2241-17.2018. Epub 2018 Feb 15.
Sleep spindles are a cardinal feature in human NREM sleep and may be important for memory consolidation. We studied the intracortical organization of spindles in men and women by recording spontaneous sleep spindles from different cortical layers using linear microelectrode arrays. Two patterns of spindle generation were identified using visual inspection, and confirmed with factor analysis. Spindles (10-16 Hz) were largest and most common in upper and middle channels, with limited involvement of deep channels. Many spindles were observed in only upper or only middle channels, but approximately half occurred in both. In spindles involving both middle and upper channels, the spindle envelope onset in middle channels led upper by ∼25-50 ms on average. The phase relationship between spindle waves in upper and middle channels varied dynamically within spindle epochs, and across individuals. Current source density analysis demonstrated that upper and middle channel spindles were both generated by an excitatory supragranular current sink while an additional deep source was present for middle channel spindles only. Only middle channel spindles were accompanied by deep low (25-50 Hz) and high (70-170 Hz) gamma activity. These results suggest that upper channel spindles are generated by supragranular pyramids, and middle channel by infragranular. Possibly, middle channel spindles are generated by core thalamocortical afferents, and upper channel by matrix. The concurrence of these patterns could reflect engagement of cortical circuits in the integration of more focal (core) and distributed (matrix) aspects of memory. These results demonstrate that at least two distinct intracortical systems generate human sleep spindles. Bursts of ∼14 Hz oscillations, lasting ∼1 s, have been recognized for over 80 years as cardinal features of mammalian sleep. Recent findings suggest that they play a key role in organizing cortical activity during memory consolidation. We used linear microelectrode arrays to study their intracortical organization in humans. We found that spindles could be divided into two types. One mainly engages upper layers of the cortex, which are considered to be specialized for associative activity. The other engages both upper and middle layers, including those devoted to sensory input. The interaction of these two spindle types may help organize the interaction of sensory and associative aspects of memory consolidation.
睡眠纺锤波是人类非快速眼动睡眠的主要特征，可能对记忆巩固很重要。我们通过使用线性微电极阵列记录来自不同皮质层的自发性睡眠纺锤波，研究了男性和女性的皮质内纺锤波组织。通过视觉检查识别出两种纺锤波生成模式，并通过因子分析进行了确认。纺锤波（10-16 Hz）在较高和中间通道中最大且最常见，而在深部通道中则有限。许多纺锤波仅在较高或仅在中间通道中观察到，但大约有一半发生在两者中。在涉及中间和较高通道的纺锤波中，中间通道中的纺锤波包络在较高通道之前平均领先约 25-50 ms。在纺锤波期间，上通道和中间通道中的纺锤波相位关系在通道内和个体间均动态变化。电流源密度分析表明，上通道和中间通道的纺锤波均由兴奋性的超颗粒电流汇产生，而中间通道的纺锤波仅由深部源产生。仅中间通道的纺锤波伴随着深部低（25-50 Hz）和高（70-170 Hz）γ活动。这些结果表明，上通道的纺锤波由超颗粒锥体产生，而中间通道的纺锤波由颗粒下产生。可能的是，中间通道的纺锤波由核心丘脑皮质传入纤维产生，而上通道的纺锤波由基质产生。这些模式的同时出现可能反映了皮质回路的参与，以整合更集中（核心）和分布式（基质）的记忆方面。这些结果表明，至少有两个不同的皮质内系统产生人类睡眠纺锤波。80 多年来，持续约 1 s 的约 14 Hz 振荡爆发被认为是哺乳动物睡眠的主要特征。最近的研究结果表明，它们在记忆巩固期间组织皮质活动中起着关键作用。我们使用线性微电极阵列研究了它们在人类中的皮质内组织。我们发现，纺锤波可以分为两种类型。一种主要涉及大脑皮层的上层，而上层被认为是专门用于联想活动的。另一种则涉及上和中间层，包括那些专门用于感觉输入的层。这两种纺锤波类型的相互作用可能有助于组织感觉和联想方面的记忆巩固的相互作用。
