Hippocampus-Dependent Strengthening of Targeted Memories via Reactivation during Sleep in Humans
Hippocampus-Dependent Strengthening of Targeted Memories via Reactivation during Sleep in Humans
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DOI：
10.1016/j.cub.2013.07.006
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发表时间：
2013-09-23
期刊：
影响因子：
9.2
通讯作者：
Rodriguez-Fornells, Antoni
中科院分区：
文献类型：
--
作者：
Fuentemilla, Lluis;Miro, Julia;Rodriguez-Fornells, Antoni
最近在动物和人类身上积累的证据表明，记忆强化至少部分发生在睡眠期间[1,2]，并且依赖于个体记忆片段的隐蔽再激活[3-5]。然而，海马体是否通过睡眠中个体记忆的重新激活来关键地促进记忆巩固仍有待确定。为了研究这种现象在人类中的海马依赖性，我们选择了两组患有选择性单侧（TLE+UHS）或双侧（TLE+BHS）海马硬化的慢性颞叶癫痫（TLE）患者和一组匹配的健康对照，并要求他们学习提示单词出现的声音关联。在健康人群中其他类似的行为范式的基础上[4,6]，在夜间慢波睡眠阶段（SWS）再次呈现仅提示一半学习记忆的声音，从而促进一组精选编码事件的记忆再激活。第二天进行的记忆测试显示，仅在对照组和TLE+UHS患者中观察到再激活记忆的加强。重要的是，记忆增强的数量是通过空闲海马的体积来预测的。因此，海马体的结构完整性越高，记忆再激活带来的记忆获益程度越高。最后，睡眠特定的神经生理反应，如纺锤波和慢波，在样本组之间是不同的，在SWS期间的纺锤波密度预测了第2天观察到的记忆改善程度。综上所述，这些发现表明，海马体在睡眠期间通过隐蔽的再激活巩固记忆方面起着至关重要的作用。
Recent accumulating evidence in animals and humans has shown that memory strengthening occurs, at least partially, during sleep [1, 2] and relies on the covert reactivation of individual memory episodes [3-5]. However, it remains to be determined whether the hippocampus critically promotes memory consolidation via the reactivation of individual memories during sleep. To investigate the hippocampal-dependent nature of this phenomenon in humans, we selected two groups of chronic temporal lobe epileptic (TLE) patients with selective unilateral (TLE+UHS) or bilateral (TLE+BHS) hippocampal sclerosis and a group of matched healthy controls, and we requested them to learn the association of sounds cueing the appearance of words. On the basis of other similar behavioral paradigms in healthy populations [4, 6], sounds that cued only half of the learned memories were presented again during the slow-wave sleep stage (SWS) at night, thus promoting memory reactivation of a select set of encoded episodes. A memory test administered on the subsequent day showed that the strengthening of reactivated memories was observed only in the control subjects and TLE+UHS patients. Importantly, the amount of memory strengthening was predicted by the volume of spared hippocampus. Thus, the greater the structural integrity of the hippocampus, the higher the degree of memory benefit driven by memory reactivation. Finally, sleep-specific neurophysiological responses, such as spindles and slow waves, differed between the sample groups, and the spindle density during SWS predicted the degree of memory benefit observed on day 2. Taken together, these findings demonstrate that the hippocampus plays a crucial role in the consolidation of memories via covert reactivation during sleep.