Gozal D, Omidvar O, Kirlew K A, Hathout G M, Lufkin R B, Harper R M
Department of Neurobiology, University of California, Los Angeles School of Medicine 90095, USA.
J Clin Invest. 1996 Jan 1;97(1):47-53. doi: 10.1172/JCI118405.
Obstructive lung disease is the most common form of respiratory disturbance. However, the location of brain structures underlying the ventilatory response to resistive expiratory loads is unknown in humans. To study this issue, midsagittal magnetic resonance images were acquired in eight healthy volunteers before and after application of a moderate resistive expiratory load (30 cmH2O/liter/s), using functional magnetic resonance imaging (fMRI) strategies (1.5-T magnetic resonance; repetition time: 72 ms; echo time: 45 ms; flip angle: 30 degrees; field of view: 26 cm; slice thickness: 5 mm; 128 x 256 x 1 number of excitations). Digital image subtractions and region of interest analyses revealed significant increases in fMRI signal intensity in discrete areas of the ventral medulla, ventral and dorsal pontomedullary structures, basal forebrain, and cerebellum. Upon load withdrawal, a rapid fMRI signal off-transient occurred in all activated sites. Application of an identical load immediately after recovery from the initial stimulus resulted in smaller signal increases (P < 0.02). Prolongation of load duration was associated with progressive fMRI signal decrease across activated regions. In three additional subjects, the threshold for significant MRI signal increases was established at expiratory loads > or = 15 cmH2O/liter/s and was dose dependent with increasing loads. We conclude that resistive expiratory loads > or = 15 cmH2O/liter/s elicit regional activation of discrete brain locations in humans.
阻塞性肺病是呼吸功能障碍最常见的形式。然而，在人类中，对呼气阻力负荷通气反应的脑结构位置尚不清楚。为了研究这个问题，我们使用功能磁共振成像（fMRI）策略（1.5-T磁共振；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；激发次数：128×256×1），在8名健康志愿者施加中等呼气阻力负荷（30厘米水柱/升/秒）前后采集了正中矢状面磁共振图像。数字图像减法和感兴趣区域分析显示，延髓腹侧、脑桥延髓腹侧和背侧结构、基底前脑和小脑的离散区域的fMRI信号强度显著增加。负荷撤除后，所有激活部位均出现快速的fMRI信号关断瞬变。从初始刺激恢复后立即施加相同负荷，信号增加较小（P<0.02）。负荷持续时间延长与激活区域的fMRI信号逐渐降低有关。在另外三名受试者中，显著MRI信号增加的阈值在呼气负荷≥15厘米水柱/升/秒时确定，且与负荷增加呈剂量依赖性。我们得出结论，呼气阻力负荷≥15厘米水柱/升/秒会引起人类离散脑区的局部激活。
