Centre de Recherche de l'Institut du Cerveau et de la Moelle Epinière-INSERM Unité Mixte de Recherche en Santé 975-Centre National de la Recherche Scientifique Unité Mixte de Recherche 7225, Hôpital de la Pitié-Salpêtrière, Paris, France.
J Neurosci. 2010 Jun 9;30(23):7770-82. doi: 10.1523/JNEUROSCI.5049-09.2010.
Gamma oscillations (40-120 Hz), usually associated with waking functions, can be recorded in the deepest stages of sleep in animals. The full details of their large-scale coordination across multiple cortical networks are still unknown. Furthermore, it is not known whether oscillations with similar characteristics are also present in the human brain. In this study, we examined the existence of gamma oscillations during polysomnographically defined sleep-wake states using large-scale microelectrode recordings (up to 56 channels), with single-cell and spike-time precision, in epilepsy patients. We report that low (40-80 Hz) and high (80-120 Hz) gamma oscillations recurrently emerged over time windows of several hundreds of milliseconds in all investigated cortical areas during slow-wave sleep. These patterns were correlated with positive peaks of EEG slow oscillations and marked increases in local cellular discharges, suggesting that they were associated with cortical UP states. These gamma oscillations frequently appeared at approximately the same time in many different cortical areas, including homotopic regions, forming large spatial patterns. Coincident firings with millisecond precision were strongly enhanced during gamma oscillations but only between cells within the same cortical area. Furthermore, in a significant number of cases, cortical gamma oscillations tended to occur within 100 ms after hippocampal ripple/sharp wave complexes. These data confirm and extend earlier animal studies reporting that gamma oscillations are transiently expressed during UP states during sleep. We speculate that these high-frequency patterns briefly restore "microwake" activity and are important for consolidation of memory traces acquired during previous awake periods.
γ 振荡（40-120Hz）通常与觉醒功能相关，可在动物的最深睡眠阶段记录到。其在多个皮质网络中的大规模协调的全部细节仍然未知。此外，人类大脑中是否也存在具有类似特征的振荡尚不清楚。在这项研究中，我们使用癫痫患者的大电极记录（多达 56 个通道），以单细胞和尖峰时间精度，检查了在多导睡眠图定义的睡眠-觉醒状态下γ 振荡的存在。我们报告说，在慢波睡眠期间，在所有研究的皮质区域中，低频（40-80Hz）和高频（80-120Hz）γ 振荡随着数百毫秒的时间窗口反复出现。这些模式与 EEG 慢波的正峰和局部细胞放电的显著增加相关，表明它们与皮质 UP 状态有关。这些γ 振荡经常在许多不同的皮质区域中同时出现，包括同型区域，形成大的空间模式。在γ 振荡期间，毫秒精度的同时发射被强烈增强，但仅在同一皮质区域内的细胞之间。此外，在大量情况下，皮质γ 振荡倾向于在海马回波/锐波复合体后 100ms 内发生。这些数据证实并扩展了早期的动物研究报告，即在睡眠期间 UP 状态下短暂表达γ 振荡。我们推测这些高频模式短暂恢复“微觉醒”活动，对于巩固在之前清醒期间获得的记忆痕迹非常重要。
