A Resting-state fMRI Investigation of Brain Networks in Spinocerebellar Ataxia Type 3

Spinocerebellar ataxia type 3 (SCA3) is characterised by disconnection within the cerebellar-cerebral network. In the present study, we examined differences in this network between healthy controls (n = 14) and individuals with SCA3 (n = 14) using resting-state functional magnetic resonance imaging. Using cerebellar Crus I as the seed region, we focused on the frontoparietal network and the default-mode network, as both are well-established but remain under-characterised in the SCA3 population. Additionally, we examined non-specific connectivity with 115 other brain regions, based on the Automated Anatomical Labelling atlas, as a control condition. Individuals with SCA3 exhibited reduced functional connectivity within cerebellar-cerebral networks. We identified both network specificity and hemispheric lateralisation in SCA3-related neurodegeneration, particularly implicating the left frontoparietal network. In conclusion, this study provides preliminary evidence of altered functional connectivity between Crus I and the frontoparietal network in SCA3. Future research may consider this network as a potential exploratory outcome measure in SCA3 clinical trials.