Mapping the Cerebellum to the Neural Network of Reading in Bilinguals

Abstract

Neuroimaging studies have proposed that reading operates via two routes in the cerebral cortex; a sub-lexical dorsal route which maps written letters to corresponding sounds, and a lexical ventral route where corresponding phonological forms are retrieved for the whole written forms. Despite evidence of cerebellar activity during language processes, less is known about the cerebellum’s role in reading, and whether different writing systems modulate cerebellar activity in reading for bilinguals. Thus, we aimed to assess cerebellar involvement in reading processes and hypothesised differential activation of the right Lobule VI and right Crus I for lexical reading processes, and the right Lobule VI, right Crus II, and right Lobule VIIB for sub-lexical reading processes. The findings clearly support cerebellar involvement in reading and indicate lateralisation of cerebellar functions in reading, consistent with the right cerebellar hemisphere association with language-related processes. However, the proposed hypotheses were partially supported as the right Lobule VI and VIIB were implicated in both sub-lexical and lexical processing in reading. Contrary to predictions, the right Crus II was involved in lexical reading processes, which is, nonetheless, consistent with findings of semantic prediction processes in the region. Findings for Crus I could have been limited due to the relatively less task demands on semantic processing. In sum, the findings underscore the need for further research on the heterogeneity of cerebellar functions and cerebro-cerebellar functional connectivity to develop a comprehensive understanding of the neural correlates of reading.