Animal studies have shown robust electrophysiological activity in the sensory cortex in the absence of stimuli or tasks. Similarly, recent human functional magnetic resonance imaging (fMRI) revealed widespread, spontaneously emerging cortical fluctuations. However, it is unknown what neuronal dynamics underlie this spontaneous activity in the human brain. Here we studied this issue by combining bilateral single-unit, local field potentials (LFPs) and intracranial electrocorticography (ECoG) recordings in individuals undergoing clinical monitoring. We found slow (<0.1 Hz, following 1/f-like profiles) spontaneous fluctuations of neuronal activity with significant interhemispheric correlations. These fluctuations were evident mainly in neuronal firing rates and in gamma (40-100 Hz) LFP power modulations. Notably, the interhemispheric correlations were enhanced during rapid eye movement and stage 2 sleep. Multiple intracranial ECoG recordings revealed clear selectivity for functional networks in the spontaneous gamma LFP power modulations. Our results point to slow spontaneous modulations in firing rate and gamma LFP as the likely correlates of spontaneous fMRI fluctuations in the human sensory cortex.

中文翻译：

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人类感觉皮层中揭示的缓慢自发神经元波动的半球间相关性。


动物研究表明，在没有刺激或任务的情况下，感觉皮层具有强大的电生理活动。同样，最近的人类功能磁共振成像（fMRI）显示出广泛的、自发出现的皮质波动。然而，尚不清楚人脑中这种自发活动的神经元动力学是什么。在这里，我们通过结合接受临床监测的个体的双侧单单位局部场电位（LFP）和颅内皮质电图（ECoG）记录来研究这个问题。我们发现神经元活动的缓慢（<0.1 Hz，遵循 1/f 型分布）自发波动具有显着的半球间相关性。这些波动主要在神经元放电率和伽马（40-100 Hz）LFP 功率调制中表现明显。值得注意的是，在快速眼球运动和第二阶段睡眠期间，大脑半球间的相关性得到了增强。多个颅内 ECoG 记录揭示了自发伽玛 LFP 功率调制中功能网络的明确选择性。我们的结果表明，放电率和伽玛 LFP 的自发调节很慢，这可能与人类感觉皮层的自发功能磁共振成像波动相关。