Recent studies have documented the involvement of the posterior cerebellar Crus (I & II) in social mentalizing, when sequences play a critical role. We investigated for the first time implicit learning of belief sequences. We created a novel task in which true and false beliefs of other persons were alternated in an adapted serial reaction time (SRT) paradigm (Belief SRT task). Participants observed two protagonists whose beliefs concerning reality were manipulated, depending on their orientation toward the scene (true belief: directly observing the situation) or away from it (false belief: knowing only the prior situation). Unbeknownst to the participants, a fixed sequence related to the two protagonists’ belief orientations was repeated throughout the task (Training phase); and to test the acquisition of this fixed sequence, it was occasionally interrupted by random sequences (Test phase). As a nonsocial control, the two protagonists and their orientations were replaced by two different shapes of different colors respectively (Control SRT task). As predicted, the posterior cerebellar Crus I & II were activated during the Belief SRT task and not in the Control SRT task. The Belief SRT task revealed that Crus I was activated during the initial learning of the fixed sequence (Training phase) and when this learned sequence was interrupted by random sequences (Test phase). Moreover, Crus II was activated during occasional reappearance of the learned sequence in the context of sequence violations (Test phase). Our results demonstrate the contribution of the posterior cerebellar Crus during implicit learning and predicting new belief sequences.

最近的研究记录了小脑后腿 (I & II) 在社会心理化中的参与，当序列起着关键作用时。我们首次研究了信念序列的内隐学习。我们创建了一项新任务，其中其他人的真假信念在适应的连续反应时间 (SRT) 范式中交替出现（信念 SRT 任务）。参与者观察了两个主角，他们对现实的信念被操纵，这取决于他们对场景的取向（真实信念：直接观察情况）或远离场景（错误信念：只知道先前的情况）。在参与者不知情的情况下，在整个任务（训练阶段）中重复了与两个主角的信念取向相关的固定序列；并测试这个固定序列的获取，它偶尔会被随机序列打断（测试阶段）。作为非社会控制，两个主角和他们的方向分别被两种不同颜色的不同形状所取代（控制SRT任务）。正如预测的那样，小脑后部 I 和 II 在 Belief SRT 任务期间被激活，而不是在 Control SRT 任务中被激活。Belief SRT 任务显示 Crus I 在固定序列的初始学习（训练阶段）以及该学习序列被随机序列中断时（测试阶段）被激活。此外，在序列违规（测试阶段）的情况下，在学习序列偶尔重新出现期间，Crus II 被激活。我们的结果证明了小脑后腿在隐式学习和预测新信念序列期间的贡献。