Examining the Cerebral-Cerebellar Connectivity During Spelling Tasks

The cerebellum has long been implicated in language processes, but its precise role in spelling subcomponents such as orthographic retrieval and phoneme-grapheme conversion planning remains underexplored. We used task-based fMRI and functional connectivity (FC) analyses to investigate cerebral-cerebellar cooperation during three in-scanner spelling conditions that differentially taxed print, and sound processes in 33 adults with and without reading impairments. ROI-to-ROI analyses identified robust cerebral-cerebellar connectivity across all conditions, with task-specific engagement of cerebellar regions in right lobule VI and Crus II. Despite marked behavioral differences between typical and impaired readers, including lower spelling accuracy and slower response times in the impaired group, no significant group differences in cerebral-cerebellar FC were observed. Generalized psychophysiological interaction (gPPI) analyses revealed unique cerebral-cerebellar connectivity patterns associated with sublexical processing (e.g., left supramarginal gyrus to right lobule VIb) in the phonological task, but not in the orthographic condition. These findings support a dynamic and context-dependent cerebellar role in language processing and suggest that cerebellar contributions to spelling involve integrative cooperation with cerebral language regions regardless of reading proficiency. This study reinforces the need to consider cerebellar-cortical networks in models of reading and dyslexia.