Department of Psychology, Carl von Ossietzky University of Oldenburg, Oldenburg, Germany.
Hum Brain Mapp. 2019 Jan;40(1):151-162. doi: 10.1002/hbm.24361. Epub 2018 Sep 25.
Reach movements are characterized by multiple kinematic variables that can change with age or due to medical conditions such as movement disorders. While the neural control of reach direction is well investigated, the elements of the neural network regulating speed (the nondirectional component of velocity) remain uncertain. Here, we used a custom made magnetic resonance (MR)-compatible arm movement tracking system to capture the real kinematics of the arm movements while measuring brain activation with functional magnetic resonance imaging to reveal areas in the human brain in which BOLD-activation covaries with the speed of arm movements. We found significant activation in multiple cortical and subcortical brain regions positively correlated with endpoint (wrist) speed (speed-related activation), including contralateral premotor cortex (PMC), supplementary motor area (SMA), thalamus (putative VL/VA nuclei), and bilateral putamen. The hand and arm regions of primary sensorimotor cortex (SMC) and a posterior region of thalamus were significantly activated by reach movements but showed a more binary response characteristics (movement present or absent) than with continuously varying speed. Moreover, a subregion of contralateral SMA also showed binary movement activation but no speed-related BOLD-activation. Effect size analysis revealed bilateral putamen as the most speed-specific region among the speed-related clusters whereas primary SMC showed the strongest specificity for movement versus non-movement discrimination, independent of speed variations. The results reveal a network of multiple cortical and subcortical brain regions that are involved in speed regulation among which putamen, anterior thalamus, and PMC show highest specificity to speed, suggesting a basal-ganglia-thalamo-cortical loop for speed regulation.
伸手运动的特征是多个运动学变量，这些变量可能随年龄或运动障碍等医学状况而变化。虽然已经很好地研究了伸手方向的神经控制，但调节速度（速度的无方向分量）的神经网络的要素仍然不确定。在这里，我们使用定制的磁共振（MR）兼容的手臂运动跟踪系统来捕获手臂运动的真实运动学，同时使用功能磁共振成像测量大脑激活，以揭示大脑中与手臂运动速度相关的 BOLD 激活的区域。我们发现多个皮质和皮质下脑区的显著激活与端点（手腕）速度呈正相关（与速度相关的激活），包括对侧运动前区（PMC）、辅助运动区（SMA）、丘脑（假定 VL/VA 核）和双侧壳核。初级感觉运动皮层（SMC）的手和手臂区域以及丘脑的一个后区域在伸手运动时被显著激活，但与连续变化的速度相比，其反应特征更具二元性（存在或不存在运动）。此外，对侧 SMA 的一个亚区也显示出二元运动激活，但没有与速度相关的 BOLD 激活。效应大小分析显示，双侧壳核是与速度相关的簇中最具速度特异性的区域，而初级 SMC 对运动与非运动的区分表现出最强的特异性，与速度变化无关。结果揭示了一个涉及速度调节的多个皮质和皮质下脑区网络，其中壳核、前丘脑和 PMC 对速度的特异性最高，表明速度调节的基底节-丘脑-皮质环路。
