Department of Psychology, University of Michigan, Ann Arbor, MI 48109, USA.
Brain Res. 2011 Mar 22;1380:187-97. doi: 10.1016/j.brainres.2010.10.102. Epub 2010 Nov 1.
Healthy individuals show robust functional connectivity during rest, which is stronger in adults than in children. Connectivity occurs between the posterior and anterior portions of the default network, a group of structures active in the absence of a task, including the posterior cingulate cortex and the superior frontal gyrus. Previous studies found weaker posterior-anterior connectivity in the default network in adults and adolescents with autism spectrum disorders (ASD). However, these studies used small a priori regions of interest ("seeds") to calculate connectivity. Since seed location for all participants was chosen based on controls' brains, these studies' analyses are more tailored to controls than individuals with ASD. An alternative is to use a data-driven approach, such as self-organizing maps (SOM), to create a reference for each participant to calculate connectivity. We used individualized resting-state clusters identified by an SOM algorithm to corroborate previous findings of weaker posterior-anterior connectivity in the ASD group and examine age-related changes in the ASD and control groups. Thirty-nine adolescents with ASD and 41 controls underwent a 10-minute, eyes-open, resting-state functional MRI scan. The SOM analysis revealed that adolescents with ASD versus controls have weaker connectivity between the posterior hub of the default network and the right superior frontal gyrus. Additionally, controls have larger increases in connectivity with age compared to the ASD group. These findings indicate that SOM is a complementary method for calculating connectivity in a clinical population. Additionally, adolescents with ASD have a different developmental trajectory of the default network compared to controls.
健康个体在休息时表现出强大的功能连接，这种连接在成年人中比在儿童中更强。连接发生在默认网络的后段和前段之间，默认网络是一组在没有任务时活跃的结构，包括后扣带皮层和额上回。先前的研究发现，自闭症谱系障碍（ASD）患者的成年人和青少年的默认网络中后-前连接较弱。然而，这些研究使用了小的预先设定的感兴趣区域（“种子”）来计算连接。由于所有参与者的种子位置都是基于对照组的大脑选择的，因此这些研究的分析更适合对照组，而不是 ASD 患者。另一种方法是使用数据驱动的方法，如自组织映射（SOM），为每个参与者创建一个参考来计算连接。我们使用 SOM 算法识别的个体化静息状态聚类来证实 ASD 组中较弱的后-前连接的先前发现，并检查 ASD 和对照组的年龄相关变化。39 名 ASD 青少年和 41 名对照组接受了 10 分钟的睁眼静息态功能 MRI 扫描。SOM 分析显示，与对照组相比，ASD 患者的默认网络后端枢纽与右侧额上回之间的连接较弱。此外，与 ASD 组相比，对照组的连接随年龄增长的幅度更大。这些发现表明 SOM 是一种在临床人群中计算连接的补充方法。此外，与对照组相比，ASD 青少年的默认网络发育轨迹不同。
