Change in Brain Blood Flow before and after Chewing Using Near-Infrared Spectroscopy

本实验的目的是阐明咀嚼运动与脑血流量之间的关系。40名20多岁的健康受试者（20名男性和20名女性）被要求用他们习惯咀嚼的一侧咀嚼一块口香糖。同时用肌电图记录咬肌活动，用激光血流量仪记录体表血流，用近红外光谱（NIRS）记录前额和颞区深部血流。研究了咀嚼过程中前额和颞叶深层血流量的变化，并将脑血流量与咬肌活动积分值进行了比较。虽然咀嚼过程中前额的表面血流量没有变化，但咀嚼过程中前额的深层血流量增加并恢复到原来的状态。实验证实，本实验使用的装置可以在不受肌肉活动影响的情况下检测到脑血流量，并且颞叶前区的探头也可以检测到脑血流量。咀嚼时脑血流量增加，咀嚼停止后脑血流量减少。咬肌活动积分值和脑血流量积分值在弱期最小，中强期依次增大。在这两个时期之间发现了显著的差异。从这些结果可以得出结论，咀嚼运动确实增加了脑血流量，肌肉活动的强度影响了脑血流量的变化。

The purpose of this experiment was to clarify the relationship between masticatory movement and brain blood flow.Forty healthy subjects (20 males and 20 females) in their twenties were asked to chew a piece of chewing gum on their habitual chewing side. The masseter muscular activity using EMG, the surface blood flow using laser bloody flow meter, and the deep blood flow of the forehead and temporal region using NIRS (Near-infrared spectroscopy) were recorded simultaneously. The change of the deep blood flow of the forehead and the temporal region during mastication were investigated and then compared between the amount of blood flow in the brain and the integral values of masseter muscular activities.Though the surface blood flow of the forehead did not change during mastication, the deep blood flow of the forehead increased during mastication and returned to its original state. It was confirmed that the device used in this experiment could detect the brain blood flow without the influence of muscular activity, and the probe of the anterior temporal region also could detect the brain blood flow.The brain blood flow increased during mastication and decreased when mastication ceased and returned to its original state. And the integral values of masseter muscular activity and the blood flow in the brain were smallest at weak period and increased in order of medium period and strong period. A significant difference was found between the periods. From, these results it was concluded that the blood flow in the brain did increase by masticatory movement and the strength of the muscular activity affected the changes of brain blood flow.