Likova Lora T, Mineff Kristyo N, Nicholas Spero C
Smith-Kettlewell Eye Research Institute, San Francisco, CA, United States.
Front Syst Neurosci. 2021 Sep 10;15:655514. doi: 10.3389/fnsys.2021.655514. eCollection 2021.
It is generally understood that the main role of the cerebellum is in movement planning and coordination, but neuroimaging has led to striking findings of its involvement in many aspects of cognitive processing. Mental visualization is such a cognitive process, extensively involved in learning and memory, artistic and inventive creativity, etc. Here, our aim was to conduct a multidimensional study of cerebellar involvement in the non-motor cognitive tasks. First, we used fMRI to investigate whether the cognitive task of visualization from an immediate memory of complex spatial structures (line drawings) engages the cerebellum, and identified a cerebellar network of both strongly activated and suppressed regions. Second, the task-specificity of these regions was examined by comparative analysis with the task of perceptual exploration and memorization of the drawings to be later visualized from memory. BOLD response patterns over the iterations of each task differed significantly; unexpectedly, the suppression grew markedly stronger in visualization. Third, to gain insights in the organization of these regions into cerebellar networks, we determined the directed inter-regional causal influences using Granger Causal Connectivity analysis. Additionally, the causal interactions of the cerebellar networks with a large-scale cortical network, the Default Mode Network (DMN), were studied. Fourth, we investigated rapid cognitive learning in the cerebellum at the level of short-term BOLD response evolution within each region of interest, and at the higher level of network reorganization. Our paradigm of interleaved sequences of iteration between two tasks combined with some innovative analyses were instrumental in addressing these questions. In particular, rapid forms of non-motor learning that strongly drive cerebellar plasticity through mental visualization were uncovered and characterized at both sub-lobular and network levels. Collectively, these findings provide novel and expansive insights into high-order cognitive functions in the cerebellum, and its macroscale functional neuroanatomy. They represent a basis for a framework of rapid cerebellar reorganization driven by non-motor learning, with implications for the enhancement of cognitive abilities such as learning and memory.
人们普遍认为，小脑的主要作用在于运动规划与协调，但神经影像学研究发现小脑在认知加工的诸多方面都有显著参与。心理视觉化就是这样一种认知过程，广泛涉及学习与记忆、艺术与发明创造等。在此，我们的目的是对小脑在非运动认知任务中的参与情况进行多维度研究。首先，我们使用功能磁共振成像（fMRI）来探究从复杂空间结构（线条图）的即时记忆进行视觉化的认知任务是否会激活小脑，并确定了一个由强烈激活和抑制区域组成的小脑网络。其次，通过与对要从记忆中进行视觉化的图形进行感知探索和记忆的任务进行对比分析，来检验这些区域的任务特异性。每个任务迭代过程中的血氧水平依赖（BOLD）反应模式有显著差异；出乎意料的是，在视觉化任务中抑制作用明显增强。第三，为了深入了解这些区域在小脑网络中的组织方式，我们使用格兰杰因果连接分析来确定区域间的定向因果影响。此外，还研究了小脑网络与大规模皮质网络——默认模式网络（DMN）之间的因果相互作用。第四，我们在每个感兴趣区域内的短期BOLD反应演变水平以及更高层次的网络重组水平上，研究了小脑中的快速认知学习。我们将两个任务之间的迭代交错序列范式与一些创新分析相结合，有助于解决这些问题。特别是，通过心理视觉化强烈驱动小脑可塑性的非运动学习的快速形式在小叶和网络层面都被发现并进行了特征描述。总的来说，这些发现为小脑的高阶认知功能及其宏观功能神经解剖学提供了新颖而广泛的见解。它们代表了一个由非运动学习驱动的小脑快速重组框架的基础，对学习和记忆等认知能力的提升具有重要意义。
