Brain Function for Enjoying Meal-Study by Using Positron CT

首先，这项研究的目的是使用FDG-PET来量化下颌侧移过程中咀嚼肌和大脑的局部和整体活动。11名咀嚼功能正常的健康年轻男性志愿者参与研究。每个受试者都接受了肘静脉注射39.2+/-5.2MBq的18F-FDG。注射后即刻，要求每个受试者以1.0赫兹的频率开始下颌骨左侧偏移，然后持续30min。结果显示，对侧翼外肌和翼内肌的SURS值均显著高于双侧咬肌。不同受试者咀嚼肌在功能过程中的FDG积累量差异较大，各受试者的肌肉活动呈现出个性化的特点。然而，正电子发射计算机断层扫描(PET)图像很难表征咀嚼口香糖时的脑活动，因此，功能磁共振成像(FMRI)也被应用于分析咀嚼口香糖时的脑功能。在MR扫描仪(西门子Magnetom Vision Plus，1.5T)中，受试者(三名男性)被要求以仰卧位佩戴耳塞执行以下任务：作为味觉刺激的口香糖和橙色口香糖，以及作为视觉刺激的橙色和橙色马赛克切割表面的投影图像。结合这些刺激，在四种情况下进行磁共振成像。结果显示，在同时施加味觉刺激和视觉刺激时，顶叶和颞叶的活动明显多于同时施加视觉刺激时的活动。另一方面，橙子图像和遮挡图像作为视觉刺激对有无味觉刺激的大脑活动的差异没有影响。

At first, the study was designed to quantify the local and overall activity of masticatory muscles and the brain during lateral excursion of the mandible using FDG-PET. Eleven healthy young male volunteers who had normal masticatory function participated in the study. Each subject received an injection of 39.2 +/-5.2 MBq of ^<18>F-FDG into the cubital vein. Just after the injection, each subject was asked to start left lateral excursion of the mandible at 1.0 Hz and then continued for 30 min. As results, the mean SURs of contralateral lateral pterygoid and medial pterygoid muscles were significantly higher than those of the bilateral masseter muscles. There was large variation in the FDG accumulation of the masticatory muscles during function among subjects and muscle activities of each subject showed individual manner. However it was difficult to characterize the brain activities during mandibular function by PET images.Therefore functional magnetic resonance imaging (fMRI) was also applied to analyze the brain function during gum chewing. In the MR Scanner (Siemens Magnetom Vision Plus, 1.5T), subjects (three males) wearing earplugs in a supine position were instructed to perform the following task : chewing gum with no taste and orange taste as taste stimuli and watching the projected images of the cutting surface of an orange and an orange colored mosaic as visual stimuli. Combining these stimuli, MR imaging under four conditions were carried out. As results, much activities in the parietal and temporal lobes were observed when both of taste and visual stimuli were applied than when both were not. On the other hand, the image of an orange and the occluded image as visual stimuli had no effect on the difference between the brain activities with and without taste stimuli.