Siwek Donald F, Knapp Clifford M, Kaur Gurcharan, Datta Subimal
Laboratory of Sleep and Cognitive Neuroscience, Department of Psychiatry, Boston University School of Medicine, 85 East Newton Street, Suite M-902, Boston, MA, 02118, USA.
Exp Brain Res. 2014 May;232(5):1535-45. doi: 10.1007/s00221-014-3858-4. Epub 2014 Feb 14.
The neurobiological mechanisms of emotional memory processing can be investigated using classical fear conditioning as a model system, and evidence from multiple lines of research suggests that sleep influences consolidation of emotional memory. In rodents, some of this evidence comes from a common finding that sleep deprivation from 0 to 6 h after fear conditioning training impairs processing of conditioned fear memory. Here, we show that during a 6-h session of sleep-wake (S-W) recording, immediately after a session of context-associated fear conditioning training, rats spent more time in wakefulness (W) and less time in slow-wave sleep (SWS) and rapid eye movement (REM) sleep. This context-associated fear conditioning training-induced reduction in SWS lasts for 2 h, and the REM sleep reduction lasts throughout the entire 6-h post-training S-W recording period. Interestingly, these reductions in SWS and REM sleep during this 6-h period did not impair memory consolidation for context-associated fear conditioning. The results of this study show, for the first time, that lesions within the dorsal part of the subcoeruleus nucleus (SubCD), which were unintentionally caused by the implantation of bipolar recording electrodes, impair consolidation of context-associated fear conditioning memory. Together, the results of these experiments suggest that emotional memory processing associated with fear conditioning can be completed successfully within less than a normal amount of sleep, but it requires a structurally and functionally intact SubCD, an area in the brain stem where phasic pontine wave (P-wave) generating cells are located.
情绪记忆加工的神经生物学机制可通过使用经典恐惧条件反射作为模型系统进行研究，多条研究线索的证据表明睡眠会影响情绪记忆的巩固。在啮齿动物中，部分证据来自一个常见发现，即恐惧条件反射训练后0至6小时的睡眠剥夺会损害条件性恐惧记忆的加工。在此，我们表明，在与情境相关的恐惧条件反射训练 session 之后立即进行的6小时睡眠-觉醒（S-W）记录过程中，大鼠在清醒（W）状态下花费的时间更多，而在慢波睡眠（SWS）和快速眼动（REM）睡眠中花费的时间更少。这种与情境相关的恐惧条件反射训练引起的SWS减少持续2小时，而REM睡眠减少在整个训练后6小时的S-W记录期内持续存在。有趣的是，在这6小时期间SWS和REM睡眠的这些减少并未损害与情境相关的恐惧条件反射的记忆巩固。本研究结果首次表明，双极记录电极植入无意导致的蓝斑下核背侧部分（SubCD）损伤会损害与情境相关的恐惧条件反射记忆的巩固。总之，这些实验结果表明，与恐惧条件反射相关的情绪记忆加工可以在少于正常睡眠量的情况下成功完成，但它需要一个结构和功能完整的SubCD，即脑干中产生相位性脑桥波（P波）的细胞所在的区域。
