Breathing rhythm, emotions and memories

Abstract

This review summarized a link between respiration and olfaction, and discussed new insights into the olfactory-related respiratory function for emotion and memory. The respiratory center in the medulla generates a basic respiratory rhythm that is modulated by inputs from brain regions involved in processing sensory information and emotions. Olfaction is closely related to respiratory activity, as inspired olfactory information ascends directly to the limbic system. This direct input rapidly induces emotional changes accompanied by alternating respiratory rhythms. Autobiographical odor memory (AM-odor) accompanied by a sense of realism of a specific memory elicits strong emotions, and also increased arousal levels and the vividness of memories, and was associated with a deep and slow breathing pattern. Functional magnetic resonance imaging (fMRI) analysis indicated robust activation in the left posterior OFC (L-POFC) during AM-odor. We detected several trends in connectivity between L-POFC and bilateral precuneus, bilateral rostral dorsal anterior cingulate cortex (rdACC), and left parahippocampus. Among above areas, slow breathing observed in AM-odor was correlated with rdACC activation, meaning that subjects with slow breathing tend to increased activation in rdACC. Negative emotions such as anxiety and fear have been reported to increase respiratory frequency. Slow breathing associated with rdACC may provide insight into the potential inhibitory mechanisms of excessive activation of the amygdala observed anxiety and stress situations.