Baena Daniel, Fang Zhuo, Gibbings Aaron, Smith Dylan, Ray Laura B, Doyon Julien, Owen Adrian M, Fogel Stuart M
Sleep Unit, University of Ottawa Institute of Mental Health Research at The Royal, Ottawa, ON, Canada.
School of Psychology, University of Ottawa, Ottawa, ON, Canada.
Front Neurosci. 2023 Jan 18;16:1090045. doi: 10.3389/fnins.2022.1090045. eCollection 2022.
Spindles are often temporally coupled to slow waves (SW). These SW-spindle complexes have been implicated in memory consolidation that involves transfer of information from the hippocampus to the neocortex. However, spindles and SW, which are characteristic of NREM sleep, can occur as part of this complex, or in isolation. It is not clear whether dissociable parts of the brain are recruited when coupled to SW vs. when spindles or SW occur in isolation. Here, we tested differences in cerebral activation time-locked to uncoupled spindles, uncoupled SW and coupled SW-spindle complexes using simultaneous EEG-fMRI. Consistent with the "," we hypothesized that brain activations time-locked to coupled SW-spindles would preferentially occur in brain areas known to be critical for sleep-dependent memory consolidation. Our results show that coupled spindles and uncoupled spindles recruit distinct parts of the brain. Specifically, we found that hippocampal activation during sleep is not uniquely related to spindles. Rather, this process is primarily driven by SWs and SW-spindle coupling. In addition, we show that SW-spindle coupling is critical in the activation of the putamen. Importantly, SW-spindle coupling specifically recruited frontal areas in comparison to uncoupled spindles, which may be critical for the hippocampal-neocortical dialogue that preferentially occurs during sleep.
纺锤波通常在时间上与慢波（SW）相关联。这些慢波 - 纺锤波复合体与记忆巩固有关，记忆巩固涉及信息从海马体转移到新皮层。然而，作为非快速眼动睡眠特征的纺锤波和慢波，既可以作为这种复合体的一部分出现，也可以单独出现。尚不清楚当与慢波耦合时，与纺锤波或慢波单独出现时相比，大脑的不同部分是否会被激活。在这里，我们使用同步脑电图 - 功能磁共振成像测试了与未耦合的纺锤波、未耦合的慢波以及耦合的慢波 - 纺锤波复合体时间锁定的大脑激活差异。与“……”一致，我们假设与耦合的慢波 - 纺锤波时间锁定的大脑激活将优先发生在已知对睡眠依赖性记忆巩固至关重要的脑区。我们的结果表明，耦合的纺锤波和未耦合的纺锤波会激活大脑的不同部分。具体而言，我们发现睡眠期间海马体的激活并非仅与纺锤波有关。相反，这个过程主要由慢波和慢波 - 纺锤波耦合驱动。此外，我们表明慢波 - 纺锤波耦合在壳核的激活中至关重要。重要的是，与未耦合的纺锤波相比，慢波 - 纺锤波耦合特别激活了额叶区域，这可能对睡眠期间优先发生的海马体 - 新皮层对话至关重要。
