Sheets John R, Briggs Robert G, Young Isabella M, Bai Michael Y, Lin Yueh-Hsin, Poologaindran Anujan, Conner Andrew K, O'Neal Christen M, Baker Cordell M, Glenn Chad A, Sughrue Michael E
Department of Neurosurgery, University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States of America.
Cingulum Health, Sydney, Australia.
J Neurol Sci. 2021 Feb 15;421:117322. doi: 10.1016/j.jns.2021.117322. Epub 2021 Jan 18.
The supplementary motor area (SMA) plays an important role in the initiation and coordination of internally and externally cued movements. Such movements include reaching, grasping, speaking, and bilateral hand coordination. While many studies discuss the SMA and its relationship to other parts of the motor network, there is minimal literature examining the connectivity of the SMA outside of the motor network. Using region-based fMRI studies, we built a neuroanatomical model to account for these extra-motor connections.
Thirty region-based fMRI studies were used to generate an activation likelihood estimation (ALE) using BrainMap software. Cortical parcellations overlapping the ALE were used to construct a preliminary model of the SMA connections outside the motor network. DSI-based fiber tractography was performed to determine the connectivity between cortical parcellations. The resulting connections were described using the cortical parcellation scheme developed by the Human Connectome Project (HCP).
Four left hemisphere regions were found to comprise the SMA. These included areas SFL, SCEF, 6ma, and 6mp. Across mapped brains, these areas showed consistent interconnections between each other. Additionally, ipsilateral connections to the primary motor cortex, left inferior and middle frontal gyri, the anterior cingulate gyrus, and insula were demonstrated. Connections to the contralateral SMA, anterior cingulate, lateral premotor, and inferior frontal cortices were also identified.
We describe a preliminary cortical model for the underlying structural connectivity of the supplementary motor area outside the motor network. Future studies should further characterize the neuroanatomic underpinnings of this network for the purposes of medical application.
辅助运动区（SMA）在内部和外部提示运动的发起和协调中起着重要作用。这些运动包括伸手、抓握、说话和双手双侧协调。虽然许多研究讨论了SMA及其与运动网络其他部分的关系，但关于SMA在运动网络之外的连接性的文献却很少。我们利用基于区域的功能磁共振成像（fMRI）研究，构建了一个神经解剖模型来解释这些运动外连接。
使用30项基于区域的fMRI研究，通过BrainMap软件生成激活可能性估计（ALE）。与ALE重叠的皮质分区用于构建运动网络外SMA连接的初步模型。基于扩散谱成像（DSI）的纤维束成像用于确定皮质分区之间的连接性。使用人类连接体计划（HCP）开发的皮质分区方案描述所得连接。
发现左半球的四个区域构成了SMA。这些区域包括SFL、SCEF、6ma和6mp区。在所有映射的大脑中，这些区域之间显示出一致的相互连接。此外，还证明了与初级运动皮层、左额下回和额中回、前扣带回和脑岛的同侧连接。还确定了与对侧SMA、前扣带回、外侧运动前区和额下回皮质的连接。
我们描述了运动网络外辅助运动区潜在结构连接性的初步皮质模型。未来的研究应进一步表征该网络的神经解剖学基础，以用于医学应用。
