Increased scale-free dynamics in salience network in adult high-functioning autism
Increased scale-free dynamics in salience network in adult high-functioning autism
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DOI：
10.1016/j.nicl.2018.101634
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发表时间：
2019-01-01
影响因子：
4.2
通讯作者：
Northoff, Georg
中科院分区：
文献类型：
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作者：
Damiani, Stefano;Scalabrini, Andrea;Northoff, Georg
自闭症谱系障碍(ASD)的临床特征是极其缓慢和僵硬的行为。然而，这些症状的神经机制仍不清楚。利用功能磁共振成像技术，我们研究了高功能成人ASD患者与精神分裂症和神经典型受试者的静息状态在频域的时间结构(用幂定律指数(PLE)和谱熵(SE)测量的无标度活动)和时间变异(神经变异性)。我们发现ASD的特点是突出网络的PLE高，特别是在背侧前扣带回。这种PLE的增加是1)突出网络特有的；2)独立于其他指标，如神经元变异性/SD和功能连接性，没有显示出任何显著差异；3)在两个独立的ASD样本中检测到，但在精神分裂症样本中没有检测到。在突起网络亚区中，背侧前扣带回皮质在两个样本中的ASD和神经型患者中显示出不同的PLE，在ROC曲线值上显示出较高的稳健性。自旋回波证实突起网络时间结构异常，与PLE呈强反相关，ASD时突起网络时间结构异常减少。综上所述，我们的发现显示在成人高功能ASD患者的静息状态显著网络中存在异常的时间结构(但时间变化正常)。异常高的PLE表明较慢的频率相对于较快的频率相对占优势，这可能是自闭症患者对意外变化和僵化行为的缓慢适应的基础。突触网络中PLE异常的特异性提示其作为ASD生物标志物的潜在价值。
Autism spectrum disorder (ASD) is clinically characterized by extremely slow and inflexible behavior. The neuronal mechanisms of these symptoms remain unclear though. Using fMRI, we investigate the resting state's temporal structure in the frequency domain (scale-free activity as measured with Power-Law Exponent, PLE, and Spectral Entropy, SE) and temporal variance (neural variability) in high-functioning, adult ASD comparing them with schizophrenic and neurotypical subjects. We show that ASD is characterized by high PLE in salience network, especially in dorsal anterior cingulate. This increase in PLE was 1) specific for salience network; 2) independent of other measures such as neuronal variability/SD and functional connectivity, which did not show any significant difference; 3) detected in two independent samples of ASD but not in the schizophrenia sample. Among salience network subregions, dorsal anterior cingulate cortex exhibited PLE differences between ASD and neurotypicals in both samples, showing high robustness in ROC curves values. Salience network abnormal temporal structure was confirmed by SE, which was strongly anticorrelated with PLE and thus decreased in ASD. Taken together, our findings show abnormal temporal structure (but normal temporal variance) in resting state salience network in adult high-functioning ASD. The abnormally high PLE indicates a relative predominance of slower over faster frequencies, which may underlie the slow adaptation to unexpected changes and the inflexible behavior observed in autistic individuals. The specificity of abnormal PLE in salience network suggests its potential utility as biomarker in ASD.