Gozal D, Omidvar O, Kirlew K A, Hathout G M, Hamilton R, Lufkin R B, Harper R M
Department of Anatomy, University of California School of Medicine, Los Angeles 90095, USA.
Proc Natl Acad Sci U S A. 1995 Jul 3;92(14):6607-11. doi: 10.1073/pnas.92.14.6607.
Compensatory ventilatory responses to increased inspiratory loading are essential for adequate breathing regulation in a number of pulmonary diseases; however, the human brain sites mediating such responses are unknown. Midsagittal and axial images were acquired in 11 healthy volunteers during unloaded and loaded (30 cmH2O; 1 cmH2O = 98 Pa) inspiratory breathing, by using functional magnetic resonance imaging (fMRI) strategies (1.5-tesla MR; repetition time, 72 msec; echo time, 45 msec; flip angle, 30 degrees; field of view, 26 cm; slice thickness, 5 mm; number of excitations, 1; matrix, 128 x 256). Digital image subtractions and region of interest analyses revealed significantly increased fMRI signal intensity in discrete areas of the ventral and dorsal pons, interpeduncular nucleus, basal forebrain, putamen, and cerebellar regions. Upon load withdrawal, certain regions displayed a rapid fMRI signal off-transient, while in others, a slower fMRI signal decay emerged. Sustained loading elicited slow decreases in fMRI signal across activated regions, while second application of an identical load resulted in smaller signal increases compared to initial signal responses (P < 0.001). A moderate inspiratory load is associated with consistent regional activation of discrete brain locations; certain of these regions have been implicated in mediation of loaded breathing in animal models. We speculate that temporal changes in fMRI signal may indicate respiratory after-discharge and/or habituation phenomena.
对增加的吸气负荷的代偿性通气反应对于多种肺部疾病中充分的呼吸调节至关重要；然而，介导这种反应的人脑部位尚不清楚。通过使用功能磁共振成像（fMRI）策略（1.5特斯拉磁共振成像；重复时间，72毫秒；回波时间，45毫秒；翻转角，30度；视野，26厘米；层厚，5毫米；激励次数，1；矩阵，128×256），在11名健康志愿者进行无负荷和有负荷（30厘米水柱；1厘米水柱 = 98帕斯卡）吸气呼吸期间采集正中矢状面和轴位图像。数字图像减法和感兴趣区域分析显示，在腹侧和背侧脑桥、脚间核、基底前脑、壳核和小脑区域的离散区域中，fMRI信号强度显著增加。在撤除负荷后，某些区域显示出快速的fMRI信号关断瞬变，而在其他区域，则出现较慢的fMRI信号衰减。持续加载导致激活区域的fMRI信号缓慢下降，而与初始信号反应相比，再次施加相同负荷导致信号增加较小（P < 0.001）。适度的吸气负荷与离散脑区的一致区域激活有关；在动物模型中，其中某些区域已被证明与负荷呼吸的调节有关。我们推测，fMRI信号的时间变化可能表明呼吸后放电和/或习惯化现象。
