Western Institute for Neuroscience, Western University, London, Ontario, Canada.
Cognitive, Linguistics, & Psychological Science, Brown University, Providence, United States.
Elife. 2024 Jul 9;13:RP96386. doi: 10.7554/eLife.96386.
Functional magnetic resonance imaging (fMRI) studies have documented cerebellar activity across a wide array of tasks. However, the functional contribution of the cerebellum within these task domains remains unclear because cerebellar activity is often studied in isolation. This is problematic, as cerebellar fMRI activity may simply reflect the transmission of neocortical activity through fixed connections. Here, we present a new approach that addresses this problem. Rather than focus on task-dependent activity changes in the cerebellum alone, we ask if neocortical inputs to the cerebellum are gated in a task-dependent manner. We hypothesize that input is upregulated when the cerebellum functionally contributes to a task. We first validated this approach using a finger movement task, where the integrity of the cerebellum has been shown to be essential for the coordination of rapid alternating movements but not for force generation. While both neocortical and cerebellar activity increased with increasing speed and force, the speed-related changes in the cerebellum were larger than predicted by an optimized cortico-cerebellar connectivity model. We then applied the same approach in a cognitive domain, assessing how the cerebellum supports working memory. Enhanced gating was associated with the encoding of items in working memory, but not with the manipulation or retrieval of the items. Focusing on task-dependent gating of neocortical inputs to the cerebellum offers a promising approach for using fMRI to understand the specific contributions of the cerebellum to cognitive function.
功能磁共振成像（fMRI）研究记录了小脑在广泛任务中的活动。然而，由于小脑活动通常是孤立地进行研究，小脑在这些任务领域中的功能贡献仍不清楚。这是有问题的，因为小脑 fMRI 活动可能只是反映了新皮层活动通过固定连接的传递。在这里，我们提出了一种新的方法来解决这个问题。我们不是单独关注小脑在任务相关活动变化，而是询问小脑对新皮层的输入是否以任务依赖的方式进行门控。我们假设当小脑对任务有功能贡献时，输入会被上调。我们首先使用手指运动任务验证了这种方法，其中已经证明小脑的完整性对于快速交替运动的协调是必不可少的，但对于力的产生则不是。虽然新皮层和小脑活动都随着速度和力量的增加而增加，但小脑与速度相关的变化大于优化的皮质-小脑连接模型的预测。然后，我们在认知领域应用了相同的方法，评估了小脑如何支持工作记忆。增强的门控与工作记忆中项目的编码相关，而与项目的操作或检索无关。关注小脑对新皮层输入的任务依赖门控为使用 fMRI 理解小脑对认知功能的特定贡献提供了一种很有前途的方法。
