Xiao Yaqiong, Zhai Hongchang, Friederici Angela D, Jia Fucang
College of Education, Guangzhou University, No. 230 Waihuan West Road, Higher Education Mega Center, Panyu District, Guangzhou, 510006, China.
Department of Neuropsychology, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany.
Brain Imaging Behav. 2016 Mar;10(1):50-9. doi: 10.1007/s11682-015-9362-z.
In recent years, research on human functional brain imaging using resting-state fMRI techniques has been increasingly prevalent. The term "default mode" was proposed to describe a baseline or default state of the brain during rest. Recent studies suggested that the default mode network (DMN) is comprised of two functionally distinct subsystems: a dorsal-medial prefrontal cortex (DMPFC) subsystem involved in self-oriented cognition (i.e., theory of mind) and a medial temporal lobe (MTL) subsystem engaged in memory and scene construction; both subsystems interact with the anterior medial prefrontal cortex (aMPFC) and posterior cingulate (PCC) as the core regions of DMN. The present study explored the development of DMN core regions and these two subsystems in both hemispheres from 3- to 5-year-old children. The analysis of the intrinsic activity showed strong developmental changes in both subsystems, and significant changes were specifically found in MTL subsystem, but not in DMPFC subsystem, implying distinct developmental trajectories for DMN subsystems. We found stronger interactions between the DMPFC and MTL subsystems in 5-year-olds, particularly in the left subsystems that support the development of environmental adaptation and relatively complex mental activities. These results also indicate that there is stronger right hemispheric lateralization at age 3, which then changes as bilateral development gradually increases through to age 5, suggesting in turn the hemispheric dominance in DMN subsystems changing with age. The present results provide primary evidence for the development of DMN subsystems in early life, which might be closely related to the development of social cognition in childhood.
近年来，利用静息态功能磁共振成像技术对人类大脑功能成像的研究越来越普遍。“默认模式”一词被提出来描述大脑在休息时的基线或默认状态。最近的研究表明，默认模式网络（DMN）由两个功能不同的子系统组成：一个涉及自我导向认知（即心理理论）的背内侧前额叶皮质（DMPFC）子系统和一个参与记忆和场景构建的内侧颞叶（MTL）子系统；这两个子系统都与作为DMN核心区域的前内侧前额叶皮质（aMPFC）和后扣带回（PCC）相互作用。本研究探讨了3至5岁儿童两个半球中DMN核心区域和这两个子系统的发育情况。对内在活动的分析表明，两个子系统都有强烈的发育变化，并且特别在MTL子系统中发现了显著变化，而在DMPFC子系统中未发现，这意味着DMN子系统有不同的发育轨迹。我们发现5岁儿童的DMPFC和MTL子系统之间的相互作用更强，特别是在支持环境适应和相对复杂心理活动发展的左侧子系统中。这些结果还表明，3岁时右半球的偏侧化更强，然后随着双侧发育逐渐增加直至5岁而发生变化，这反过来又表明DMN子系统中的半球优势随年龄而变化。本研究结果为DMN子系统在生命早期的发育提供了初步证据，这可能与儿童期社会认知的发展密切相关。
