Moroni Fabio, Nobili Lino, Iaria Giuseppe, Sartori Ivana, Marzano Cristina, Tempesta Daniela, Proserpio Paola, Lo Russo Giorgio, Gozzo Francesca, Cipolli Carlo, De Gennaro Luigi, Ferrara Michele
Department of Psychology, "Sapienza" University of Rome, Roma, Italy; Laboratory of Psychology, Department of Specialized, Diagnostics and Experimental Medicine, University of Bologna, Bologna, Italy.
Hippocampus. 2014 Oct;24(10):1157-68. doi: 10.1002/hipo.22299. Epub 2014 May 13.
The hypothesis that sleep is instrumental in the process of memory consolidation is currently largely accepted. Hippocampal formation is involved in the acquisition of declarative memories and particularly of spatial memories. Nevertheless, although largely investigated in rodents, the relations between spatial memory and hippocampal EEG activity have been scarcely studied in humans. Aimed to evaluate the effects of spatial learning on human hippocampal sleep EEG activity, we recorded hippocampal Stereo-EEG (SEEG) in a group of refractory epilepsy patients undergoing presurgical clinical evaluation, after a training on a spatial navigation task. We observed that hippocampal high-delta (2-4 Hz range) activity increases during the first NREM episode after learning compared to the baseline night. Moreover, the amount of hippocampal NREM high-delta power was correlated with task performance at retest. The effect involved only the hippocampal EEG frequencies inasmuch no differences were observed at the neocortical electrodes and in the traditional polysomnographic measures. The present findings support the crucial role of hippocampal slow EEG frequencies during sleep in the memory consolidation processes. More generally, together with previous results, they suggest that slow frequency rhythms are a fundamental characteristic of human hippocampal EEG during both sleep and wakefulness, and are related to the consolidation of different types of memories.
睡眠在记忆巩固过程中起作用这一假说目前已被广泛接受。海马结构参与陈述性记忆尤其是空间记忆的获取。然而，尽管在啮齿动物中对此进行了大量研究，但空间记忆与海马脑电活动之间的关系在人类中却鲜有研究。为了评估空间学习对人类海马睡眠脑电活动的影响，我们在一组接受术前临床评估的难治性癫痫患者中，在其完成空间导航任务训练后，记录了海马立体脑电图（SEEG）。我们观察到，与基线夜晚相比，学习后的首个非快速眼动睡眠期海马高波（2 - 4赫兹范围）活动增加。此外，海马非快速眼动睡眠高波功率量与复测时的任务表现相关。该效应仅涉及海马脑电频率，因为在新皮质电极和传统多导睡眠图测量中未观察到差异。目前的研究结果支持了睡眠期间海马慢脑电频率在记忆巩固过程中的关键作用。更普遍地说，与先前的结果一起，它们表明慢频率节律是人类海马脑电在睡眠和清醒状态下的一个基本特征，并且与不同类型记忆的巩固有关。
