静息态fMRI评价进食前后脑默认网络变化

Resting state fMRI in evaluation of brain default mode network alteration before and after food intake

目的采用静息态fMRI评价进食前后脑默认网络(DMN)的变化。方法选取15名健康志愿者,均进食标准实验早餐,于空腹、早餐后、餐后2h及午餐前4个时间段接受静息态fMRI检查。采用独立成分分析方法提取DMN。将提取的4个时间段DMN数据进行重复测量方差分析,获得差异有统计学意义的脑区,再将其作为蒙片,提取差异脑区的功能连接Z值,并进行统计学分析。结果 4个不同时间段时,前扣带回与内侧前额叶眶回的功能连接差异有统计学意义(P<0.001,体素数目>85个)。与空腹比较,早餐后及餐后2h前扣带回与内侧前额叶眶回的功能连接Z值较小(P均<0.05);与午餐前比较,早餐后及餐后2h功能连接Z值亦较小(P<0.05);余时间段两两比较,前扣带回与内侧前额叶眶回的功能连接Z值差异均无统计学意义(P均>0.05)。结论进食前后前扣带回和内侧前额叶眶回的功能连接发生相应变化。

Objective To explore the changes of brain default mode network （DMN） before and after food intake with resting state fMRI. Methods Fifteen healthy volunteers all had standard experiment diet for breakfast. All subjects ac- cepted resting state fMRI at four different states： Fasting state, postprandial immediately, postprandial 2 hours and before lunch. DMN was extracted by independent component analysis. DMN datum at four different states were analyzed by re- peated ANOVA to obtain brain areas with statistical difference. Brain voxels with statistical difference were used as mask, and function connectivity Z value in statistical difference brain area was extracted for statistic analysis. Results Function connectivity difference in anterior cingulate cortex and medial orbital frontal cortex had statistically significant at four different states （P〈0. 001, voxel number〉85）. Compared to fasting state, the function connectivity Z value in anterior cingulate cortex and medial orbital frontal cortex reduced in postprandial immediately and postprandial 2 hours （both P〈0.05）. Compared to before lunch, the function connectivity Z value in anterior cingulate cortex and medial orbital frontal cortex also reduced in postprandial immediately and postprandial 2 hours （both P〈0.05）. The difference of function connectivity Z value in anterior cingulate cortex and medial orbital frontal cortex had no statistical significance at other two states after pairwise comparison （all P〉0. 05）. Conclusion There is corresponding alteration of function connectivity in anterior cin- gulate cortex and medial orbital frontal cortex before and after food intake.