2023年5月29日，《自然—神经科学》杂志在线发表了美国科罗拉多大学医学院Abigail L. Person课题组的最新成果。该研究表明，小脑联想学习是熟练接触适应的基础。

研究人员表示，小脑被假设为通过在线调整来完善运动。

研究人员利用小鼠伸手的范式研究了这种预测性控制是如何产生的，并测试了小脑是否使用伸手内的信息作为预测器来调整伸手运动学。研究人员首先在浦肯野细胞中发现了一个群体水平的反应，该反应与伸手速度成反比，表明小脑皮层是连接运动学预测器和预测性控制的一个潜在部位。接下来，结果表明，小鼠可以学会补偿由反复、闭环的光遗传刺激小脑苔藓纤维输入引起的可预测到达扰动。神经和行为读数都显示出对位置锁定的苔藓纤维扰动的适应，并在刺激被移除时表现出后遗症。

令人惊讶的是，位置随机的刺激时间表驱动了部分适应，但没有相反的后效应。一个再现这些发现的模型表明，小脑可能通过与时间有关的概括机制来破译因果关系。

附：英文原文

Title: Cerebellar associative learning underlies skilled reach adaptation

Author: Calame, Dylan J., Becker, Matthew I., Person, Abigail L.

Issue&Volume: 2023-05-29

Abstract: The cerebellum is hypothesized to refine movement through online adjustments. We examined how such predictive control may be generated using a mouse reach paradigm, testing whether the cerebellum uses within-reach information as a predictor to adjust reach kinematics. We first identified a population-level response in Purkinje cells that scales inversely with reach velocity, pointing to the cerebellar cortex as a potential site linking kinematic predictors and anticipatory control. Next, we showed that mice can learn to compensate for a predictable reach perturbation caused by repeated, closed-loop optogenetic stimulation of pontocerebellar mossy fiber inputs. Both neural and behavioral readouts showed adaptation to position-locked mossy fiber perturbations and exhibited aftereffects when stimulation was removed. Surprisingly, position-randomized stimulation schedules drove partial adaptation but no opposing aftereffects. A model that recapitulated these findings suggests that the cerebellum may decipher cause-and-effect relationships through time-dependent generalization mechanisms.

DOI: 10.1038/s41593-023-01347-y

Source: https://www.nature.com/articles/s41593-023-01347-y