Department of Psychology, Center for Brain Science, Harvard University, Cambridge, Massachusetts, United States.
Centre for Sleep & Cognition and Department of Electrical and Computer Engineering, National University of Singapore, Singapore, Singapore.
J Neurophysiol. 2024 Jun 1;131(6):1014-1082. doi: 10.1152/jn.00308.2023. Epub 2024 Mar 15.
The cerebral cortex is populated by specialized regions that are organized into networks. Here we estimated networks from functional MRI (fMRI) data in intensively sampled participants. The procedure was developed in two participants (scanned 31 times) and then prospectively applied to 15 participants (scanned 8-11 times). Analysis of the networks revealed a global organization. Locally organized first-order sensory and motor networks were surrounded by spatially adjacent second-order networks that linked to distant regions. Third-order networks possessed regions distributed widely throughout association cortex. Regions of distinct third-order networks displayed side-by-side juxtapositions with a pattern that repeated across multiple cortical zones. We refer to these as supra-areal association megaclusters (SAAMs). Within each SAAM, two candidate control regions were adjacent to three separate domain-specialized regions. Response properties were explored with task data. The somatomotor and visual networks responded to body movements and visual stimulation, respectively. Second-order networks responded to transients in an oddball detection task, consistent with a role in orienting to salient events. The third-order networks, including distinct regions within each SAAM, showed two levels of functional specialization. Regions linked to candidate control networks responded to working memory load across multiple stimulus domains. The remaining regions dissociated across language, social, and spatial/episodic processing domains. These results suggest that progressively higher-order networks nest outward from primary sensory and motor cortices. Within the apex zones of association cortex, there is specialization that repeatedly divides domain-flexible from domain-specialized regions. We discuss implications of these findings, including how repeating organizational motifs may emerge during development. The organization of cerebral networks was estimated within individuals with intensive, repeat sampling of fMRI data. A hierarchical organization emerged in each individual that delineated first-, second-, and third-order cortical networks. Regions of distinct third-order association networks consistently exhibited side-by-side juxtapositions that repeated across multiple cortical zones, with clear and robust functional specialization among the embedded regions.
大脑皮层由专门的区域组成，这些区域组织成网络。在这里，我们从功能磁共振成像（fMRI）数据中估计了密集采样参与者的网络。该过程是在两名参与者（扫描 31 次）中开发的，然后前瞻性地应用于 15 名参与者（扫描 8-11 次）。网络分析显示出全局组织。局部组织的一级感觉和运动网络被空间上相邻的二级网络包围，这些二级网络与远距离区域相连。三级网络具有分布在整个联合皮层的区域。具有不同三级网络的区域显示出并排相邻的排列，其模式在多个皮质区域中重复出现。我们称之为超区域联合巨簇（SAAMs）。在每个 SAAM 中，两个候选控制区域与三个独立的域专业化区域相邻。使用任务数据探索响应特性。躯体运动和视觉网络分别对身体运动和视觉刺激作出反应。二级网络对奇异性检测任务中的瞬态作出反应，这与在突出事件中定向的作用一致。三级网络，包括每个 SAAM 内的不同区域，表现出两种功能专业化水平。与候选控制网络相连的区域对多个刺激域的工作记忆负荷作出反应。其余区域在语言、社会和空间/情景处理域中分离。这些结果表明，越来越高的层次网络从初级感觉和运动皮层向外嵌套。在联合皮层的顶点区域，存在专门化，反复划分灵活的领域与专门化的领域。我们讨论了这些发现的意义，包括在发展过程中重复出现组织模式的可能性。通过对 fMRI 数据进行密集、重复采样，在个体内部估计了大脑网络的组织。在每个人中都出现了一种层次结构，它描绘了第一、第二和第三级皮质网络。不同的三级联合网络区域始终显示出并排相邻的排列，在多个皮质区域中重复出现，具有明确和稳健的嵌入区域之间的功能专业化。
