Cortico-cerebellar connectivity in reading impaired children: A probabilistic tractography study

Very little is known about cortico-cerebellar connectivity as it relates to individuals with dyslexia. Building on previous findings of decreased volume in the anterior lobe of the cerebellum, we utilized novel cerebellar segmentation procedures and probabilistic tractography to examine tracts that originate in the anterior lobe of the cerebellum and project to cortical regions typically associated with reading: the temporoparietal region (TP), occipitotemporal region (OT), and inferior frontal region (IF) in 29 children with impaired single-word readings skills and 27 typical readers. We found greater FA for the poor readers in the tracts terminating in the TP and IF regions. In the OT region, differential FA trajectories were identified such that FA was greater for the older poor readers. Additionally, behavioral correlations were found primarily within the group of typical readers. FA was inversely related to decoding. Behavioral measures were associated predominantly with TP and OT regions. This study provides evidence for discrete, regionally-bound functions of the cerebellum and suggests that the projections from the anterior cerebellum appear to have a regulatory effect on cortical functions important for reading.