Headley Drew B, Paré Denis
Center for Molecular and Behavioral Neuroscience, Rutgers State University, Newark, New Jersey, 07102.
NPJ Sci Learn. 2017;2. doi: 10.1038/s41539-016-0001-2. Epub 2017 Jan 5.
The cortex, hippocampus, and striatum support dissociable forms of memory. While each of these regions contains specialized circuitry supporting their respective functions, all structure their activities across time with delta, theta, and gamma rhythms. We review how these oscillations are generated and how they coordinate distinct memory systems during encoding, consolidation, and retrieval. First, gamma oscillations occur in all regions and coordinate local spiking, compressing it into short population bursts. Second, gamma oscillations are modulated by delta and theta oscillations. Third, oscillatory dynamics in these memory systems can operate in either a 'slow' or 'fast' mode. The slow mode happens during slow-wave sleep (SWS) and is characterized by large irregular activity in the hippocampus and delta oscillations in cortical and striatal circuits. The fast mode occurs during active waking and REM and is characterized by theta oscillations in the hippocampus and its targets, along with gamma oscillations in the rest of cortex. In waking, the fast mode is associated with the efficacious encoding and retrieval of declarative and procedural memories. Theta and gamma oscillations have the similar relationships with encoding and retrieval across multiple forms of memory and brain regions, despite regional differences in microcircuitry and information content. Differences in the oscillatory coordination of memory systems during sleep might explain why the consolidation of some forms of memory is sensitive to SWS, while others depend on REM. In particular, theta oscillations appear to support the consolidation of certain types of procedural memories during REM, while delta oscillations during SWS seem to promote declarative and procedural memories.
大脑皮层、海马体和纹状体支持不同形式的记忆。虽然这些区域各自都包含支持其特定功能的专门神经回路，但它们都通过δ波、θ波和γ波节律在时间上构建其活动。我们回顾这些振荡是如何产生的，以及它们在编码、巩固和检索过程中如何协调不同的记忆系统。首先，γ振荡出现在所有区域并协调局部放电，将其压缩成短暂的群体爆发。其次，γ振荡受到δ波和θ波振荡的调制。第三，这些记忆系统中的振荡动力学可以以“慢”或“快”模式运行。慢模式发生在慢波睡眠（SWS）期间，其特征是海马体中出现大量不规则活动以及皮层和纹状体回路中的δ振荡。快模式发生在清醒活跃期和快速眼动睡眠期，其特征是海马体及其靶点出现θ振荡，以及皮层其他区域出现γ振荡。在清醒状态下，快模式与陈述性和程序性记忆的有效编码和检索相关。尽管微回路和信息内容存在区域差异，但θ波和γ波振荡在多种记忆形式和脑区的编码和检索中具有相似的关系。睡眠期间记忆系统振荡协调的差异可能解释了为什么某些形式的记忆巩固对慢波睡眠敏感，而其他形式则依赖快速眼动睡眠。特别是，θ振荡似乎在快速眼动睡眠期间支持某些类型程序性记忆的巩固，而慢波睡眠期间的δ振荡似乎促进陈述性和程序性记忆。
