The cerebellum's role in reading: A functional MR imaging study

BACKGROUND AND PURPOSE: Long considered to have a role limited largely to m otor-related functions, the cerebellum has recently been implicated as bein g involved in both perceptual and cognitive processes, Our purpose was to d etermine whether cerebellar activation occurs during cognitive tasks that d ifferentially engage the component processes of word identification in read ing, METHODS: Forty-two neurologically normal adults underwent functional MR ima ging of the cerebellum with a gradient-echo echo-planar technique while per forming tasks designed to study the cognitive processing used in reading, A standard levels-of-processing paradigm was used, Participants mere asked t o determine whether pairs of words were written in the same case (orthograp hic processing), whether pairs of words and non-words rhymed with each othe r, respectively (phonologic assembly), and whether pairs of words belonged to the same category (semantic processing). Composite maps were generated f rom a general linear model based on a randomization of statistical parametr ic maps, RESULTS: During phonologic assembly, cerebellar activation was observed in the middle and posterior aspects of the posterior superior fissure and adja cent simple lobule and semilunar lobule bilaterally and in posterior aspect s of the simple lobule, superior semilunar lobule, and inferior semilunar l obule bilaterally. Semantic processing, however, resulted in activation in the deep nuclear region on the right and in the inferior vermis, in additio n to posterior areas active in phonologic assembly, including the simple, s uperior semilunar, and inferior semilunar lobules, CONCLUSION: The cerebellum is engaged during reading and differentially act ivates in response to phonologic and semantic tasks. These results indicate that the cerebellum contributes to the cognitive processes integral to rea ding.