抄録
We have studied the relationships between respiration-related behaviors and cortical activation in animal models and human experiment. In animal models, we demonstrated that arousal/yawning response was evoked by microinjections of various agents (L-glutamate, cyanide, Orexin, etc.) into the medial parvocellular subdivision of the paraventricular nucleus (mpPVN) in an anesthetized, spontaneously breathing rat. An arousal shift in ECoG was elicited prior to a yawning response, indicating two distinct neuronal pathways (ascending and descending ones) originated from mpPVN. This notion has been supported by recent morphological experiment. We found those cells double-stained by c-fos and CRF or c-fos and oxytocin in mpPVN, when frequent yawnings were induced, suggesting that CRF cells are responsible for cortical activation, whereas oxcytocinergic neurons cause yawning response. In human experiment, we examined effects of Zen mediation (voluntary abdominal breathing, VAB) on EEG in healthy subjects. We found a unique change in EEG when a subject continued the VAB in the eyes-closed condition. Since the eyes were closed, alpha wave was recorded from the onset of VAB. Spectral analysis of EEG revealed that low-frequency alpha band observed at the beginning of VAB disappeared 6-7 min during VAB, and another peak of the high-frequency alpha band was newly developed 7-8 min after the onset of VAB. Since urinary 5-HT level was elevated after VAB, we hypothesize that such change in alpha wave might be caused by excitation of serotonergic system, activated by rhythmic behavior. [Jpn J Physiol 54 Suppl:S53 (2004)]
