PhD Program in Behavioral Neuroscience, Department of Psychology, "Sapienza" University of Rome, Rome, Italy.
Brain Imaging Laboratory, Department of Psychology, "Sapienza" University of Rome, Via Dei Marsi, 78, 00185, Rome, Italy.
Sci Rep. 2023 Mar 27;13(1):4958. doi: 10.1038/s41598-023-31602-y.
Research on the contribution of the ipsilateral hemisphere to unilateral movements, and how it is mediated by transcallosal connections, has so far provided contradictory findings. By using dynamic causal modelling (DCM) and Parametric Empirical Bayes analyses applied to fMRI data, we sought to describe effective connectivity during pantomimed and imagined right-hand grasping within the grasping network, namely the anterior intraparietal sulcus, ventral and dorsal (PMd) premotor cortex, supplementary motor area and primary motor cortex (M1). The two-fold aim of the present work was to explore a) whether right and left parieto-frontal areas show similar connectivity couplings, and b) the interhemispheric dynamics between these regions across the two hemispheres. We detected a network architecture comparable across hemispheres during executed but not imagined grasping movements. Furthermore, during pantomimed grasping the interhemispheric crosstalk was mainly driven by premotor areas: we found an inhibitory influence from the right PMd toward the left premotor and motor areas and excitatory couplings between homologous ventral premotor and supplementary motor regions. Overall, our results support the view that dissociable components of unilateral grasping execution are encoded by a non-lateralized set of brain areas complexly intertwined by interhemispheric dynamics, whereas motor imagery obeys different principles.
对侧半球对单侧运动的贡献及其如何通过胼胝体连接进行介导的研究迄今为止提供了相互矛盾的发现。我们使用动态因果建模（DCM）和参数经验贝叶斯分析应用于 fMRI 数据，旨在描述在抓握网络内进行模拟和想象右手抓握时的有效连接，即前顶内沟、腹侧和背侧（PMd）运动前皮质、辅助运动区和初级运动皮质（M1）。本研究的双重目的是探讨：a）左右顶额叶区域是否显示出相似的连接耦合；b）这些区域之间的大脑两半球间的半球间动力学。我们在执行但不是想象的抓握运动期间检测到了跨半球的网络架构相似性。此外，在模拟抓握期间，半球间的串扰主要由运动前区域驱动：我们发现来自右侧 PMd 对左侧运动前和运动区域的抑制性影响以及同源腹侧运动前和辅助运动区域之间的兴奋性耦合。总体而言，我们的结果支持这样的观点，即单侧抓握执行的可分离成分由一组非侧化的大脑区域以复杂的半球间动态交织编码，而运动想象则遵循不同的原则。
