Department of Clinical Neuroscience, Karolinska Institutet, 17177 Stockholm, Sweden,
Donders Institute for Brain, Cognition, and Behavior, 6500 HD Nijmegen, The Netherlands.
J Neurosci. 2018 Nov 28;38(48):10286-10294. doi: 10.1523/JNEUROSCI.3360-17.2018. Epub 2018 Oct 22.
In mammals respiratory-locked hippocampal rhythms are implicated in the scaffolding and transfer of information between sensory and memory networks. These oscillations are entrained by nasal respiration and driven by the olfactory bulb. They then travel to the piriform cortex where they propagate further downstream to the hippocampus and modulate neural processes critical for memory formation. In humans, bypassing nasal airflow through mouth-breathing abolishes these rhythms and impacts encoding as well as recognition processes thereby reducing memory performance. It has been hypothesized that similar behavior should be observed for the consolidation process, the stage between encoding and recognition, were memory is reactivated and strengthened. However, direct evidence for such an effect is lacking in human and nonhuman animals. Here we tested this hypothesis by examining the effect of respiration on consolidation of episodic odor memory. In two separate sessions, female and male participants encoded odors followed by a 1 h awake resting consolidation phase where they either breathed solely through their nose or mouth. Immediately after the consolidation phase, memory for odors was tested. Recognition memory significantly increased during nasal respiration compared with mouth respiration during consolidation. These results provide the first evidence that respiration directly impacts consolidation of episodic events, and lends further support to the notion that core cognitive functions are modulated by the respiratory cycle. Memories pass through three main stages in their development: encoding, consolidation, and retrieval. Growing evidence from animal and human studies suggests that respiration plays an important role in the behavioral and neural mechanisms associated with encoding and recognition. Specifically nasal, but not mouth, respiration entrains neural oscillations that enhance encoding and recognition processes. We demonstrate that respiration also affects the consolidation stage. Breathing through the nose compared with the mouth during consolidation enhances recognition memory. This demonstrates, first, that nasal respiration is important during the critical period were memories are reactivated and strengthened. Second, it suggests that the neural mechanisms responsible may emerge from nasal respiration.
在哺乳动物中，与呼吸锁相的海马节律被认为是在感觉和记忆网络之间的信息支架和转移中起作用。这些振荡受鼻呼吸的调节，并由嗅球驱动。然后，它们传播到梨状皮层，在那里进一步向下游传播到海马体，并调节对记忆形成至关重要的神经过程。在人类中，通过口呼吸绕过鼻气流会破坏这些节律，并影响编码和识别过程，从而降低记忆表现。有人假设，在记忆被重新激活和增强的巩固过程（编码和识别之间的阶段）中，也应该观察到类似的行为。然而，在人类和非人类动物中，缺乏这种效应的直接证据。在这里，我们通过检查呼吸对情景气味记忆巩固的影响来检验这一假设。在两个单独的会话中，女性和男性参与者分别对气味进行编码，然后在清醒的 1 小时巩固阶段，他们仅通过鼻子或嘴呼吸。在巩固阶段后立即测试气味记忆。与巩固期间的口呼吸相比，鼻呼吸时识别记忆显著增加。这些结果首次提供了呼吸直接影响情景事件巩固的证据，并进一步支持了核心认知功能受呼吸周期调节的观点。记忆在其发展过程中经历三个主要阶段：编码、巩固和检索。越来越多的动物和人类研究证据表明，呼吸在与编码和识别相关的行为和神经机制中起着重要作用。具体来说，鼻呼吸而不是口呼吸可以使神经振荡同步，从而增强编码和识别过程。我们证明呼吸也会影响巩固阶段。在巩固期间通过鼻子呼吸与通过嘴呼吸相比，可增强识别记忆。这首先表明，在记忆被重新激活和增强的关键时期，鼻呼吸很重要。其次，这表明负责的神经机制可能源于鼻呼吸。
