Tzvi Elinor, Zimmermann Christoph, Bey Richard, Münte Thomas F, Nitschke Matthias, Krämer Ulrike M
Dept. of Neurology, University of Lübeck, Germany.
Institute of Psychology II, University of Lübeck, Germany.
Neuroimage Clin. 2017 Jul 15;16:66-78. doi: 10.1016/j.nicl.2017.07.012. eCollection 2017.
The cerebellum plays an important role in motor learning as part of a cortico-striato-cerebellar network. Patients with cerebellar degeneration typically show impairments in different aspects of motor learning, including implicit motor sequence learning. How cerebellar dysfunction affects interactions in this cortico-striato-cerebellar network is poorly understood. The present study investigated the effect of cerebellar degeneration on activity in causal interactions between cortical and subcortical regions involved in motor learning. We found that cerebellar patients showed learning-related increase in activity in two regions known to be involved in learning and memory, namely parahippocampal cortex and cerebellar Crus I. The cerebellar activity increase was observed in non-learners of the patient group whereas learners showed an activity decrease. Dynamic causal modeling analysis revealed that modulation of M1 to cerebellum and putamen to cerebellum connections were significantly more negative for sequence compared to random blocks in controls, replicating our previous results, and did not differ in patients. In addition, a separate analysis revealed a similar effect in connections from SMA and PMC to M1 bilaterally. Again, neural network changes were associated with learning performance in patients. Specifically, learners showed a negative modulation from right SMA to right M1 that was similar to controls, whereas this effect was close to zero in non-learners. These results highlight the role of cerebellum in motor learning and demonstrate the functional role cerebellum plays as part of the cortico-striato-cerebellar network.
作为皮质-纹状体-小脑网络的一部分,小脑在运动学习中发挥着重要作用。小脑变性患者通常在运动学习的不同方面表现出障碍,包括内隐运动序列学习。小脑功能障碍如何影响该皮质-纹状体-小脑网络中的相互作用,目前尚不清楚。本研究调查了小脑变性对参与运动学习的皮质和皮质下区域之间因果相互作用活动的影响。我们发现,小脑病变患者在两个已知参与学习和记忆的区域,即海马旁皮质和小脑 Crus I 中,表现出与学习相关的活动增加。在患者组的非学习者中观察到小脑活动增加,而学习者则表现出活动减少。动态因果模型分析显示,与对照组的随机块相比,M1 到小脑以及壳核到小脑连接的调制在序列方面显著更负,这重复了我们之前的结果,并且在患者中没有差异。此外,一项单独的分析显示,双侧从辅助运动区和运动前区到 M1 的连接也有类似的效果。同样,神经网络的变化与患者的学习表现相关。具体而言,学习者表现出从右侧辅助运动区到右侧 M1 的负调制,这与对照组相似,而非学习者的这种效应接近于零。这些结果突出了小脑在运动学习中的作用,并证明了小脑作为皮质-纹状体-小脑网络一部分所发挥的功能作用。