UCSF Center for Integrative Neuroscience and Department of Physiology, San Francisco, CA 94158, USA.
Neuron. 2012 Aug 23;75(4):700-13. doi: 10.1016/j.neuron.2012.06.014.
The replay of previously stored memories during hippocampal sharp wave ripples (SWRs) is thought to support both memory retrieval and consolidation in distributed hippocampal-neocortical circuits. Replay events consist of precisely timed sequences of spikes from CA3 and CA1 neurons that are coordinated both within and across hemispheres. The mechanism of this coordination is not understood. Here, we show that during SWRs in both awake and quiescent states there are transient increases in slow gamma (20-50 Hz) power and synchrony across dorsal CA3 and CA1 networks of both hemispheres. These gamma oscillations entrain CA3 and CA1 spiking. Moreover, during awake SWRs, higher levels of slow gamma synchrony are predictive of higher quality replay of past experiences. Our results indicate that CA3-CA1 gamma synchronization is a central component of awake memory replay and suggest that transient gamma synchronization serves as a clocking mechanism to enable coordinated memory reactivation across the hippocampal network.
在海马体尖波涟漪（SWR）期间回放先前存储的记忆被认为支持分布式海马体-新皮层回路中的记忆检索和巩固。重放事件由 CA3 和 CA1 神经元的精确定时尖峰序列组成，这些尖峰在半球内和半球间都协调一致。这种协调的机制尚不清楚。在这里，我们表明，在清醒和静止状态下的 SWR 期间，两个半球的背侧 CA3 和 CA1 网络中的慢伽马（20-50 Hz）功率和同步性会出现短暂增加。这些伽马振荡使 CA3 和 CA1 尖峰放电。此外，在清醒的 SWR 期间，更高水平的慢伽马同步性预示着过去经历的更高质量的重放。我们的研究结果表明，CA3-CA1 伽马同步是清醒记忆重放的核心组成部分，并表明短暂的伽马同步作为一种计时机制，可实现海马体网络中协调的记忆再激活。
