School of Automation, Northwestern Polytechnical University, Xi'an, China.
Cortical Architecture Imaging and Discovery Lab, Department of Computer Science and Bioimaging Research Center, The University of Georgia, Athens, GA, USA.
Brain Imaging Behav. 2021 Jun;15(3):1483-1498. doi: 10.1007/s11682-020-00347-x.
Functional mechanism of the brain and its relationship with the brain structural substrate have been an interest for multiple disciplines for centuries. Recently, gyri and sulci, two basic cortical folding patterns, have been demonstrated to act different functional roles. Specifically, a variety of functional MRI (fMRI) studies have consistently suggested that gyri represent a global functional center while sulci serve as a local functional unit under either resting state or task stimulus, which are further supported by brain structural analysis reporting that gyri have thicker cortex and denser long-distance axonal fibers. However, the consistency of such gyral-sulcal functional difference across different task stimuli, as well as its association with task conditions, remains to be explored. To this end, we used intrinsic networks as the testbed for cross-task comparison, and adopted a computational framework of dictionary learning and sparse representation of whole-brain fMRI signals to systematically examine the potential gyral-sulcal difference in signal representation residual (SRR) which reflected the degree of global functional communication. Using all seven task-based fMRI datasets in Human Connectome Project Q1 release, we found that within the intrinsic functional networks, the fMRI SRR was significantly smaller on gyral regions than on sulcal regions across different task stimuli, indicating that gyral regions were more involved in global functions of the brain and interregional communications. Moreover, the magnitudes of such gyral-sulcal difference varied across task conditions and intrinsic networks. Our work adds novel explanation and insight to the existing knowledge of functional differences between gyri and sulci.
大脑的功能机制及其与大脑结构基质的关系是多个学科几个世纪以来的研究热点。最近，脑回和脑沟这两种基本的皮质折叠模式被证明具有不同的功能作用。具体来说，各种功能磁共振成像（fMRI）研究一致表明，脑回代表一个全局的功能中心，而脑沟则在静息状态或任务刺激下充当局部功能单元，这一观点进一步得到脑结构分析的支持，该分析报告称脑回具有更厚的皮质和更密集的长距离轴突纤维。然而，这种脑回-脑沟功能差异在不同任务刺激下的一致性，以及其与任务条件的关联，仍有待探索。为此，我们使用内在网络作为跨任务比较的试验台，并采用字典学习和全脑 fMRI 信号稀疏表示的计算框架，系统地检查信号表示残差（SRR）中可能存在的脑回-脑沟差异，该残差反映了大脑全局功能通讯的程度。我们使用人类连接组计划 Q1 发布的所有七个基于任务的 fMRI 数据集，发现无论是在何种任务刺激下，内在功能网络中的 fMRI SRR 在脑回区域都显著小于脑沟区域，这表明脑回区域更参与大脑的全局功能和区域间通讯。此外，这种脑回-脑沟差异的幅度在不同的任务条件和内在网络中有所不同。我们的工作为脑回和脑沟之间的功能差异的现有知识增加了新的解释和见解。
