Brain function during dyspnea sensation

慢性阻塞性肺疾病(COPD)的早期症状是运动中的呼吸困难，严重的COPD即使在安静的呼吸中也会有呼吸困难。呼吸困难是在大脑中感觉到的。然而，呼吸困难期间的大脑功能并不是未知的。这项研究的目的是检查呼吸困难期间的脑功能。我们用脑成像技术、正电子发射断层扫描(PET)和统计参数图检测了健康受试者的阻力吸气负荷呼吸和重度COPD患者安静呼吸时的脑功能。正常对照组静息时注射18F标记的氟代脱氧葡萄糖(FDG)，另一组在施加吸气阻力后进行PET检查。重度COPD患者的PET研究仅在静息状态下进行。我们观察到脑内的激活部位和失活部位如下：1)正常组呼吸困难随着阻力负荷的增加而增加。正常组为阻性负荷呼吸。2)重度COPD患者舌回、颞上回、眶回激活，楔前回、额中回、顶上回、扣带回失活。本研究中观察到的大脑激活和失活的生理意义尚未阐明。

The early symptom of chronic obstructive pulmonary disease (COPD) is dyspnea during exercise, and severe COPD has dyspnea even while quiet breathing. Dyspnea is perceived in the brain. However, brain function during dyspnea has not been unknown. The aim of this study was to examine the brain function during dyspnea. We examined brain function during resistive inspiratory loaded breathing in healthy subjects and during quiet breathing in severe COPD patients, by using a brain imaging technique, positron emission tomography (PET) and statistical parametric mapping. PET studies were performed by injecting of fluorine 18 (18F)-labeled fluorodeoxyglucose (FDG) during resting breathing in normal control group and after applying the inspiratory resistance in another normal group. PET studies in severe COPD patients were only during resting breathing.We observed the activation sites and deactivation sites in the brain as follows.1)Dyspnea increased with increase in resistive loading in normal group. In normal group with resistive loaded breathing. The sites of precentral gyrus, postcentral gyrus, and orbital gyrus were activated, and the sites of precuneus, middle frontal gyrus, superior parietal lobe and cingulate gyrus were deactivated.2)In severe COPD patients, the sites of lingual gyrus, superior temporal gyrus, and orbital gyms were activated, and the sites of precuneus, cingulate gyrus, temporal lobe, superior parietal lobe and inferior parietal lobe were deactivated.3)Orbital gyrus was activated in both normal and COPD groups, and precuneus, cingulate gyms and superior parietal lobe were deactivated in both groups. The physiological meaning of the activation and deactivation in the brain observed in this study has not been clarified.