Department of Neurology, Division of Cognitive Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
Department of Biological Psychology, Heinrich-Heine-University, Institute of Experimental Psychology, Düsseldorf, Germany.
Brain Struct Funct. 2021 Apr;226(3):833-844. doi: 10.1007/s00429-020-02212-5. Epub 2021 Jan 22.
Several fMRI studies have shown that the superior cerebellum exhibits load-dependent activations during encoding of letters in a Sternberg verbal working memory (VWM) task. It has been hypothesized that the cerebellum regulates the acquisition of sensory data across all modalities, and thus, that VWM load activations may reflect high- vs low-load differences in sensory acquisition demands. Therefore, increased difficulty in sensory data acquisition should elicit greater activation in the cerebellum. The present fMRI study manipulated sensory acquisition in VWM by presenting visually degraded and non-degraded stimuli with high and low memory loads, thereby identifying load-dependent regions of interest in the cerebellum, and then testing if these regions showed greater activation for degraded stimuli. Results yielded partial support for the sensory acquisition hypothesis in a load-dependent region of the vermis, which showed significantly greater activation for degraded relative to non-degraded stimuli. Because eye movements did not differ for these stimulus types, and degradation-related activations were present after co-varying eye movements, this activation appears to be related to perceptual rather than oculomotor demands. In contrast to the vermis, load-sensitive regions of the cerebellar hemispheres did not show increased activation for degraded stimuli. These findings point to an overall function of association-based prediction that may underlie general cerebellar function, with perceptual prediction of stimuli from partial representations occurring in the vermis, and articulatory prediction occurring in the hemispheres.
几项 fMRI 研究表明，在上橄榄核在 Sternberg 言语工作记忆（VWM）任务中对字母进行编码时表现出与负荷相关的激活。据推测，小脑调节所有感觉模态的数据获取，因此，VWM 负荷激活可能反映了高负荷与低负荷之间在感觉获取需求上的差异。因此，在感觉数据获取方面的难度增加应引起小脑更大的激活。本 fMRI 研究通过呈现高负荷和低负荷的视觉退化和非退化刺激来在 VWM 中操纵感觉获取，从而确定小脑的与负荷相关的感兴趣区域，然后测试这些区域是否对退化刺激表现出更大的激活。结果在蚓部的一个与负荷相关的区域中部分支持了感觉获取假说，该区域对退化刺激的激活明显高于非退化刺激。由于这些刺激类型的眼动没有差异，并且在共同变因眼动后出现了与退化相关的激活，因此这种激活似乎与知觉而非眼球运动需求有关。与蚓部相反，小脑半球的负荷敏感区域对退化刺激没有表现出更大的激活。这些发现指向了基于关联的预测的总体功能，这可能是小脑一般功能的基础，来自部分表示的刺激的知觉预测发生在蚓部，而发音预测发生在半球。
