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

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 enhancement,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。

Objective:To investigate the functional characteristics of the obitofrontal cortex in adolescent depressive patients by resting-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 3.0 T 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.