Fundamental study for clarifying dysphagia : The role of upper brain in inducing swallowing

机械刺激咽部和/或喉部长期以来一直被认为会引起反射性吞咽，而与皮质情况无关。然而，视频荧光摄影(VF)研究表明，在咀嚼过程中，一些食物可能会被输送到咽部。有趣的是，在咀嚼过程完成之前，掉在咽部的药丸不会被吞咽。因此，该项目旨在寻找可能影响吞咽中心的皮质区域，其中，受试者使用脑磁图和室颤，动物使用运动学和电生理学方法。在兔子身上，可以记录和识别从摄食到吞咽的摄食行为。阐明了舌肌和咀嚼肌之间的协调，以及面颊和嘴唇肌肉在咀嚼过程中的作用。为了寻找一个可能的吞咽皮质区域，系统地刺激了兔子的大脑皮层。然后确定在咀嚼过程中促进或抑制燕子的区域。然而，没有确定单独能够引出燕子的具体区域。我们认为，在皮质发育不发达的动物中，该区域可能局限在很小的区域内，甚至可能不发育自主吞咽本身。脑磁图显示，扣带回皮质在自愿吞咽前短暂活跃约2秒，岛和盖在燕子出现之前长期活跃。由于扣带回皮质是已知的与情绪有关的区域，因此得出结论，该区域的激活可能与对食物的识别过程有关。已知岛盖与吞咽中枢有直接联系，此后该区域可能是燕子皮质兴奋的主要区域。VF研究表明，正如动物研究中所报道的那样，当人类清理嘴里的食物时，会吞咽两到三次。

Mechanical stimulation to pharyngeal and/or laryngeal region has long been believed to elicit swallow reflexively irrespective of the cortical situation. However, videofluorographic (VF) study has revealed that some food may be transported to the pharynx during mastication. Interestingly, the bolus dropped in the pharynx does not elicit swallow till the chewing process is completed. The project was thus designed to seek possible cortical regions which could affect swallowing center, in which magneto-encephalogram and VF were applied for human subjects and kinesiological and electrophysiological methods for animals.In rabbits, the ingestive behavior, from food intake to swallowing, could be recorded and identified. The coordination between tongue and masticatory muscles and the role of facial (cheek and lip) muscles during mastication were clarified. To seek a possible cortical region for swallowing, rabbit's cortex was systematically stimulated. Then the region, where swallows were facilitated or inhibited during chewing, was identified. However, no concrete region where the swallow could be elicited solely was identified. We believe that in animals with crudely developed cortex, the region may be limited in a small area or even voluntary swallow itself may not be developed.Magneto-encephalogram showed that the cingulate cortex was active for short time about 2 sec preceding voluntary swallows and the insula and operculum were active for long period till swallows occurred. Since cingulate cortex is known as a region relating to emotion, it is concluded that the activation in this region may be related to a recognition process of food. Insula and operculum is known to have a direct connection with the swallowing center, thereafter, the region may be the main one for cortical elicitation of swallows. VF studies revealed that humans swallow two or three times when they clear the mouth of mouthful food as has been reported in animal studies.