Kern Mark, Chai Krisna, Lawal Adeyemi, Shaker Reza
Division of Gastroenterology and Hepatology, Medical College of Wisconsin, Milwaukee, Wisconsin 53226, USA.
Am J Physiol Gastrointest Liver Physiol. 2009 Jul;297(1):G152-8. doi: 10.1152/ajpgi.00062.2009. Epub 2009 Apr 30.
Recent studies have demonstrated common cortical activity regions associated with esophageal acidification and swallowing. The effect of sensory signals imparted on these regions by esophageal acidification on swallow-related brain activity has physiological and clinical ramifications. Our aim in this study was to determine the effect of prior, unperceived esophageal acid exposure on cortical activity associated with swallowing. Functional magnetic resonance imaging (fMRI) techniques monitored brain activity associated with volitional swallowing before and after subliminal esophageal acid stimulation. Studies were carried out in two phases. In phase I (15 healthy, right-handed subjects, age 21-49 yr, 7 female) using whole brain imaging, we documented the potentiating effects of esophageal acidification alone on swallow-related cortical activity. In phase II (10 healthy, right-handed subjects, age 20-54 yr, 5 female) using high-resolution fMRI, we measured swallow-induced regional brain activity within the cortical swallowing network before and after esophageal acidification. Unlike the phase I studies, we also tested the effect of saline perfusion alone on the cortical swallowing network in the phase II studies. Because of constraints imposed by high-resolution MRI for region-of-interest (ROI) analysis, we studied only the left hemisphere in this phase. None of the subjects developed heartburn during acid perfusion. In phase I, the number of swallow-induced activated voxels increased by 43% following esophageal acid stimulation (preacid, 44 +/- 3 voxels; postacid, 63 +/- 6 voxels; means +/- SE, P < 0.05) In phase II, contrary to saline perfusion, ROI analysis showed significantly increased regional swallow-related fMRI activity volumes as well as percent maximum signal change after esophageal acid perfusion in cingulate, prefrontal, insula, and sensory/motor regions (P < 0.05). The precuneus showed no significant change. We concluded that subliminal esophageal acid stimulation has a potentiating effect on the cortical swallowing network in healthy individuals.
最近的研究已经证明了与食管酸化和吞咽相关的共同皮质活动区域。食管酸化施加于这些区域的感觉信号对吞咽相关脑活动的影响具有生理和临床意义。本研究的目的是确定先前未被察觉的食管酸暴露对与吞咽相关的皮质活动的影响。功能磁共振成像（fMRI）技术监测了阈下食管酸刺激前后与自主吞咽相关的脑活动。研究分两个阶段进行。在第一阶段（15名健康的右利手受试者，年龄21 - 49岁，7名女性），使用全脑成像，我们记录了单独食管酸化对吞咽相关皮质活动的增强作用。在第二阶段（10名健康的右利手受试者，年龄20 - 54岁，5名女性），使用高分辨率fMRI，我们测量了食管酸化前后皮质吞咽网络内吞咽诱导的局部脑活动。与第一阶段的研究不同，在第二阶段的研究中，我们还测试了单独盐水灌注对皮质吞咽网络的影响。由于高分辨率MRI对感兴趣区域（ROI）分析的限制，在这个阶段我们只研究了左半球。在酸灌注过程中，没有受试者出现烧心症状。在第一阶段，食管酸刺激后吞咽诱导的激活体素数量增加了43%（酸刺激前，44±3个体素；酸刺激后，63±6个体素；平均值±标准误，P<0.05）。在第二阶段，与盐水灌注相反，ROI分析显示，在扣带回、前额叶、岛叶和感觉/运动区域，食管酸灌注后与吞咽相关的fMRI活动体积以及最大信号变化百分比显著增加（P<0.05）。楔前叶没有显著变化。我们得出结论，阈下食管酸刺激对健康个体的皮质吞咽网络有增强作用。
