青少年首发抑郁症脑眶额叶静息态功能磁共振研究

Resting-state functional magnetic resonance imaging of orbitofrontal cortex in first-onset depressive adolescents

摘要:

目的：研究青少年抑郁症患者静息态功能磁共振（resting-state functional magnetic resonance imaging，rs-fMRI）眶额叶的功能特点。方法：选择符合DSM-IV抑郁症诊断标准的71名青少年患者作为病例组，同时收集年龄、性别相匹配的44名健康被试作为对照组，2组被试均接受3.0 T磁共振仪扫描，获取大脑结构像与血氧水平依赖成像的静息态功能像数据，应用软件DPABI进行数据处理，采用低频振荡振幅（amplitude of low-frequency fluctuation，ALFF）的方法，探索2组被试大脑眶额叶静息态低频段（0.01~0.1 Hz）的功能活动情况，采用置换检验（permutation test）与无阈值簇群增强（threshold-free cluster enhance－ment，TFCE）校正方法进行统计分析。以大脑眶额叶ALFF差异脑区作为感兴趣区（region of interest，ROI），比较其与双侧丘脑、杏仁核、前中后扣带回及海马的功能连接（functional connectivity，FC）在2组被试之间的差异。结果：与健康组相比，抑郁组大脑左侧眶额叶zALFF值明显下降（t=-2.23，P<0.05），zALFF值降低脑区与左侧丘脑的功能连接明显下降（P=0.024）。结论：青少年抑郁症患者大脑眶额叶功能活动相对于健康组有明显异常，眶额叶功能异常可能与青少年抑郁症的病理生理机制有关。

Abstract:

Objective：To investigate the functional characteristics of the obitofrontal cortex in adolescent depressive patients by rest－ing-state functional magnetic resonance imaging（rs-fMRI）. Methods：A total of 71 adolescent depressive patients meeting DSM-IV diagnostic criteria were taken as case group，and 44 age-and sex-matched healthy adolescents as control group. Both group were scanned by 3.0T MRI scanner，and rs-fMRI data and T1-weighted images were obtained and processed with DPABI. Data were analyzed by amplitude of low-frequency fluctuation（ALFF） to obtain resting-state information between 0.01 to 0.1 Hz in orbital frontal cortex. Final results were subjected to permutation test and corrected by threshold-free cluster enhancement（TFCE）. Region of interest（ROI） was drawn for each subject based on the significantly changed brain area in ALFF. Functional connectivity（FC） was performed between ROI and bilateral thalamus and 12 limbic areas：bilateral amygdala，anterior-，middle- and posterior cingulate cortex，and hippocampus. Results：Compared with the healthy group，zALFF value of the left obitofrontal cortex reduced in the depression group（t=-2.23，P<0.05）. FC value showed that FC of the obitofrontal cortex and left thalamus decreased（P=0.024）. Conclusion：Compared with the healthy group，functional activities of the obitofrontal cortex show obvious abnormalities in patients with adolescent depression，which may be correlated with the pathophysiological mechanism of adolescent depression.