不同动机特质在静息态下脑功能的相关研究

摘要

目的：动机特质包括趋近系统（BAS）和行为抑制系统（BIS），利用静息态功能MRI研究不同动机特质的被试在静息态下大脑活动的差别，以及与默认网络（DMN）、背侧注意网络（DAN）和额顶控制网络（FPN）之间功能连接强度的相关性。方法将38例完成BIS/BAS问卷的健康在校女大学生分为3组：高BAS低BIS组（高BAS组），高BIS低BAS组（高BIS组），低BAS低BIS组（对照组）。采集静息态fMRI及结构像数据并进行预处理及统计。计算低频振幅（ALFF）值，将高BAS组及高BIS组分别与对照组比较，利用双样本t检验的统计学方法，得出显著差异的脑区。利用种子相关分析法获得3个脑网络并获得其间的功能连接强度，将功能连接强度同每个被试BAS、BIS得分进行Spearman相关分析。结果两实验组与对照组比较，ALFF值呈显著性增高的脑区分别为：高BAS组主要位于左侧距状回、左侧楔前叶、后扣带回皮质、右侧尾状核、两侧前扣带回皮质、左侧额中回；高BIS组主要位于右侧顶下小叶、额叶、颞叶、距状回及左侧后扣带回。 ALFF值呈显著性减低的脑区分别为：高BAS组主要位于两侧丘脑、右侧颞上回及左侧顶叶；高BIS组主要位于左侧顶叶、额叶及两侧前扣带回。 BAS分值与DMN-FPN、DAN-FPN功能连接强度呈显著相关（r=0.69，P＜0.001；r=-0.40，P=0.037）；BIS分值与DMN-DAN功能连接强度呈显著相关（r=-0.41，P=0.036）。结论静息态下不同动机特质呈现前额叶偏侧化活动。动机特质与网络间功能连接强度存在一定相关性。动机特质是多个脑区组成的网络水平负载的神经活动。%Objebtive Motivation traits include motivational approach system (BAS) and behavioral inhibition system (BIS). To analyze brain activity of different motivational traits in resting-state, and to test the relationships between functional connectivity and trait approach/avoidance motivationby using resting state functional magnetic resonance imaging technology. Methods A total of 38 healthy college students completed BIS/ BAS questionnaire, and were classified into three groups:high BAS group who had high BAS low BIS, high BIS group (high BIS low BAS),and control group (low BAS low BIS).Resting-state fMRI scan and sagittal structural images were collected. All preprocessing steps and statistics were carried out. The high BAS group and high BIS group were compared to the control group respectively.The brain areas with significant difference were detected by a two-sample t test. The Seed-based Correlation Analysis was used to explore functional connectivity for three predefined networks.Spearman test was used to analyze the relationships between functional connectivity and trait approach/avoidance motivation. Results Compared to the control group, amplitude of low-frequency fluctuation (ALFF) was significantly increased at left calcarine cortices, precuneus, posterior cingulate cortex (PCC), and middle frontal gyri (MFG), right caudate nucleus, and bilateral anterior cingulate cortex (ACC) in the high BAS group;at the right frontal lobe, temporal lobe, inferior parietal lobule, calcarine cortices, and the left PCC in the high BIS group. ALFF was significantly decreased at the bilateral thalamus, right superior temporal gyriand, and left parietal lobe in the high BAS group;at the left frontal lobe, parietal lobe, and bilateral ACC in the high BIS group. The BAS score was significantly correlated with the strength between DMN-FPN, and DAN-FPN (r=0.69,P<0.001; r=-0.40,P=0.037, respectively), the BIS score was significantly correlated with DMN-FPN(r=-0.41,P=0.036).Conclusions Prefrontal asymmetry on different motivational traits exists in resting-state. Trait approach motivation and trait avoidance motivation are significantly correlated with functionalconnectivity.The motivational trait isaneural activity involved multiple brain areas.