Department of Medicine and Radiology, Melbourne Medical School, The University of Melbourne, Victoria, Australia.
Vascular Bionics Laboratory, Melbourne Brain Centre, Department of Medicine, The University of Melbourne, Victoria, Australia.
Hum Brain Mapp. 2018 Jun;39(6):2635-2650. doi: 10.1002/hbm.24029. Epub 2018 Mar 8.
Performing voluntary movements involves many regions of the brain, but it is unknown how they work together to plan and execute specific movements. We recorded high-resolution ultra-high-field blood-oxygen-level-dependent signal during a cued ankle-dorsiflexion task. The spatiotemporal dynamics and the patterns of task-relevant information flow across the dorsal motor network were investigated. We show that task-relevant information appears and decays earlier in the higher order areas of the dorsal motor network then in the primary motor cortex. Furthermore, the results show that task-relevant information is encoded in general initially, and then selective goals are subsequently encoded in specifics subregions across the network. Importantly, the patterns of recurrent information flow across the network vary across different subregions depending on the goal. Recurrent information flow was observed across all higher order areas of the dorsal motor network in the subregions encoding for the current goal. In contrast, only the top-down information flow from the supplementary motor cortex to the frontoparietal regions, with weakened recurrent information flow between the frontoparietal regions and bottom-up information flow from the frontoparietal regions to the supplementary cortex were observed in the subregions encoding for the opposing goal. We conclude that selective motor goal encoding and execution rely on goal-dependent differences in subregional recurrent information flow patterns across the long-range dorsal motor network areas that exhibit graded functional specialization.
执行自愿运动涉及大脑的许多区域,但尚不清楚它们如何协同工作以规划和执行特定的运动。我们在提示性踝关节背屈任务期间记录了高分辨率超高场血氧水平依赖信号。研究了背侧运动网络中跨区的时空动力学和与任务相关的信息流模式。我们表明,与任务相关的信息首先出现在背侧运动网络的较高阶区域,然后出现在初级运动皮层。此外,结果表明,与任务相关的信息最初以一般方式进行编码,然后在网络中的特定亚区中随后以特定目标进行编码。重要的是,跨网络的递归信息流模式因目标而异而变化。在编码当前目标的亚区中观察到跨整个背侧运动网络的所有高阶区域的递归信息流。相比之下,仅在编码对立目标的亚区中观察到从补充运动皮层到额顶区域的自上而下信息流,以及额顶区域之间的弱递归信息流和从前顶区域到补充皮质的下传信息流。我们得出的结论是,选择性运动目标的编码和执行依赖于长程背侧运动网络区域中与目标相关的亚区递归信息流模式的差异,这些模式表现出分级功能专业化。