Focus Lab, Department of Psychology, University of Turin, Turin, Italy.
GCS-fMRI, Koelliker Hospital and Department of Psychology, University of Turin, Turin, Italy.
Sci Rep. 2019 Mar 4;9(1):3346. doi: 10.1038/s41598-019-40188-3.
Homotopic connectivity (HC) is the connectivity between mirror areas of the brain hemispheres. It can exhibit a marked and functionally relevant spatial variability, and can be perturbed by several pathological conditions. The voxel-mirrored homotopic connectivity (VMHC) is a technique devised to enquire this pattern of brain organization, based on resting state functional connectivity. Since functional connectivity can be revealed also in a meta-analytical fashion using co-activations, here we propose to calculate the meta-analytic homotopic connectivity (MHC) as the meta-analytic counterpart of the VMHC. The comparison between the two techniques reveals their general similarity, but also highlights regional differences associated with how HC varies from task to rest. Two main differences were found from rest to task: (i) regions known to be characterized by global hubness are more similar than regions displaying local hubness; and (ii) medial areas are characterized by a higher degree of homotopic connectivity, while lateral areas appear to decrease their degree of homotopic connectivity during task performance. These findings show that MHC can be an insightful tool to study how the hemispheres functionally interact during task and rest conditions.
同伦连接（HC）是大脑半球镜像区域之间的连接。它可以表现出明显的、具有功能相关性的空间变异性，并且可以被多种病理状况所干扰。体素镜像同伦连接（VMHC）是一种基于静息态功能连接来探究这种大脑组织模式的技术。由于功能连接也可以通过共激活以元分析的方式揭示出来，因此我们在这里提出计算元分析同伦连接（MHC）作为 VMHC 的元分析对应物。两种技术的比较揭示了它们的一般相似性，但也突出了与 HC 从任务到休息变化相关的区域差异。从休息到任务发现了两个主要差异：（i）已知以全局中枢为特征的区域比显示局部中枢的区域更为相似；（ii）内侧区域表现出更高程度的同伦连接，而外侧区域在任务执行期间似乎降低了同伦连接的程度。这些发现表明，MHC 可以成为研究大脑在任务和休息条件下如何进行功能交互的有价值的工具。
