Yamaguchi Masahiro
Department of Physiology, Kochi Medical School, Kochi University, Kohasu, Okocho, Nankoku, Kochi, 783-8505, Japan.
Neurosci Res. 2017 May;118:21-29. doi: 10.1016/j.neures.2017.03.014. Epub 2017 May 10.
The central olfactory system mediates a variety of odor-guided behaviors crucial for maintenance of animal life. The olfactory neural circuit must be highly plastic to ensure that it responds appropriately to changing odor circumstances. Recent studies have revealed that the processing of odor information changes drastically during waking and sleep and that neural activity during sleep plays pivotal roles in the structural reorganization and functional plasticity of the olfactory system. While olfactory information from the external world is efficiently transferred to the olfactory cortex (OC) via the olfactory bulb (OB) during waking, this information flow is attenuated during slow-wave sleep: during slow-wave sleep, the OC neurons exhibit synchronous discharges without odor input under the entrainment of sharp waves in the local field potential recording. Top-down transfer of sharp-wave activity to the OB during slow-wave sleep promotes structural reorganization of the OB neural circuit. Further, the activity of the OC during sleep is affected by the olfactory experience during prior waking period, and perturbation of the sleep activity disrupts proper olfactory memory. Thus, as is seen also in the hippocampus and neocortex, the neural activities of the olfactory system during sleep likely play essential roles in circuit reorganization and memory consolidation.
中枢嗅觉系统介导多种对动物生存至关重要的气味引导行为。嗅觉神经回路必须具有高度可塑性，以确保其对不断变化的气味环境做出适当反应。最近的研究表明，气味信息的处理在清醒和睡眠期间会发生巨大变化，并且睡眠期间的神经活动在嗅觉系统的结构重组和功能可塑性中起着关键作用。在清醒状态下，来自外部世界的嗅觉信息通过嗅球（OB）有效地传递到嗅觉皮层（OC），而在慢波睡眠期间，这种信息流会减弱：在慢波睡眠期间，OC神经元在局部场电位记录中的尖波夹带下，在没有气味输入的情况下表现出同步放电。慢波睡眠期间尖波活动自上而下传递到OB促进了OB神经回路的结构重组。此外，睡眠期间OC的活动受先前清醒期嗅觉体验的影响，睡眠活动的扰动会破坏正常的嗅觉记忆。因此，正如在海马体和新皮层中所看到的那样，睡眠期间嗅觉系统的神经活动可能在回路重组和记忆巩固中起着重要作用。
