Study of brain plasticity and functional and psychological adaptability caused by alteration of oral environment

我们利用功能性磁共振成像（fMRI）来评估咀嚼过程中大脑活动的变化。本研究中使用的fMRI采集方案已在我们的试点研究中进行了优化。6名成年男性受试者（平均23.2岁）被告知使用咬合夹板7天。在使用咬合夹板后第1、3、7天及移除咬合夹板后第7天进行功能磁共振成像（fMRI）检查。fMRI采集后，用“视觉模拟量表”记录受试者的主观感觉。使用SPM2（统计参数映射2）分析fMRI数据，以确定使用和不使用咬合夹板的脑活动差异（未经校正的p=0.001，范围阈值=20体素）。在使用咬合夹板的第1天，使用咬合夹板后小脑和左额叶中回（BA10）的活性明显高于未使用咬合夹板。这些结果表明，在“运动学习”过程中，小脑和额叶被激活。在使用咬合夹板的第3天和第7天，小脑和额叶的活动无明显差异。在移除咬合夹板后第7天，有咬合夹板的左侧运动前皮质比没有咬合夹板的左侧运动前皮质更活跃。这些结果表明，移除咬合夹板后，与咀嚼运动新模式相对应的大脑神经网络得以构建和维持。虽然我们分析了VAS主观感觉评分与SPM2脑活动之间的相关性，但没有发现明显的相关性。

We evaluated brain function using functional magnetic resonance image (fMRI) to demonstrate brain activity change of mastication. fMRI acquisition protocol used in the present study has been optimised in our pilot study. 6 adult male subjects (mean age 23.2) were told to use occlusal splint for 7 days. fMRI was performed on day 1, 3, 7 of occlusal splint use and day 7 after occlusal splint removal. After fMRI acquisition, subjective sensations of every subject were recorded with "Visual Analog Scale". fMRI data were analyzed with SPM2 (Statistical Parametric Mapping 2) to determine differences of brain activity between with and without occlusal Splint (p=0.001 uncorrected, extent threshold=20voxels). On day 1 of occlusal splint use, cerebellum and left middle frontal gyrus (BA10) were more activated with occlusal splint than without it. These results showed the activation of cerebellum and frontal lobe during "motor learning". On day 3 and 7 of occlusal splint use, no difference of activity was detected in cerebellum and frontal lobe. On day 7 after occlusal splint removal, left premotor cortex was more activated with occlusal splint than without it. These findings suggest that brain neural network corresponding to new pattern of masticatory movement was constructed and maintained after occlusal splint removal. Although we analyzed association between subjective sensation score by VAS and brain activity using SPM2, no significant correlation was observed.