New York University Neuroscience Institute, New York, NY 10016, USA; Department of Neuroscience, Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY 10027, USA.
New York University Neuroscience Institute, New York, NY 10016, USA.
Cell Rep. 2018 Nov 13;25(7):1693-1700.e4. doi: 10.1016/j.celrep.2018.10.066.
Hippocampal sharp-wave ripples (SPW-Rs) support consolidation of recently acquired episodic memories and planning future actions by generating ordered neuronal sequences of previous or future experiences. SPW-Rs are characterized by several spectral components: a slow (5-15 Hz) sharp-wave, a high-frequency "ripple" oscillation (150-200 Hz), and a slow "gamma" oscillation (20-40 Hz). Using laminar hippocampal recordings and optogenetic manipulations, we dissected the origin of these spectral components. We show that increased power in the 20-40 Hz band does not reflect an entrainment of CA1 and CA3 neurons at gamma frequency but the power envelope of overlapping ripples. Spike-local field potential coupling between unit firing in CA1 and CA3 regions during SPW-Rs is lowest in the gamma band. Longer SPW-Rs are preceded by increased firing in the entorhinal cortex. Thus, fusion of SPW-Rs leads to lengthening of their duration associated with increased power in the slow gamma band without the presence of true oscillation.
海马体尖波涟漪 (SPW-Rs) 通过生成先前或未来经验的有序神经元序列，支持最近获得的情景记忆的巩固和未来行动的规划。SPW-Rs 的特征是具有几个谱分量：慢 (5-15 Hz) 尖波、高频“涟漪”振荡 (150-200 Hz) 和慢“伽马”振荡 (20-40 Hz)。使用层状海马记录和光遗传学操作，我们剖析了这些谱分量的起源。我们表明，20-40 Hz 频带中的功率增加并不反映 CA1 和 CA3 神经元在伽马频率下的同步，而是重叠涟漪的功率包络。在 SPW-Rs 期间，CA1 和 CA3 区域中单位放电的尖峰-局部场电位耦合在伽马频带中最低。较长的 SPW-Rs 之前是内嗅皮层中放电增加。因此，SPW-Rs 的融合导致其持续时间延长，与慢伽马频带中功率增加相关，而不存在真正的振荡。
