Cerebellar contributions to visual attention and working memory

Abstract

Attention and working memory (WM) are processes that enable the efficient prioritization or storage of a subset of available information. Consequently, a substantial body of work has sought to determine the specific brain structures that support attention and WM. To date, this literature has predominantly focused on the contributions of a limited set of cortical areas referred to as the dorsal attention network (DAN). The cerebellum, a subcortical structure traditionally implicated in motor control, has received scant consideration as a locus of attentional control, despite findings of robust anatomical and functional connectivity between cerebellum and DAN areas. This project comprises several functional magnetic resonance imaging experiments aimed at elucidating the role of the cerebellum in attention and WM (n = 38; 20-38 years). The functional implications of cortico-cerebellar DAN connectivity have received only modest scientific attention. Experiment 1 examined the hypothesis that cortico-cerebellar DAN functional connectivity predicts recruitment by canonical visual WM and attention tasks. Task-driven responses of DAN-coupled cerebellar areas were found to mirror those of their cortical counterparts. These results argue for the reconceptualization of the DAN as a cortico-cerebellar network. Previous work indicates that the functional topography of the cerebellum is relatively coarse compared with cerebral cortex. Experiment 2 examined the organization of closely related aspects of visual attention and WM within the cerebellum, and found that spatial attention and visual WM recruit overlapping yet dissociable portions of cerebellar lobule VIIb/VIIIa. This functional organization was further shown to be predicted by fine-scale patterns of functional connectivity with occipito-parietal cortex. These findings indicate that the functional specificity of cerebellar cortex mirrors that of cerebral cortex and provides direct empirical support for the hypothesis that functional specialization within the cerebellum arises due to variation in afferent input. Experiment 3 tested the hypothesis that the cerebellum can be specifically implicated in the persistent representation of information in WM. Lobule VIIb/VIIIa delay-period activity patterns were shown to exhibit stimulus-selectivity, a critical marker of WM storage processes. These results indicate that lobule VIIb/VIIIa contains a robust representation of a stimulus stored in WM, thereby refuting long-standing cortico-centric models of WM maintenance.2021-02-10T00:00:00