Cerebellar Nuclei Dysfunction in Spinocerebellar Ataxia Type 1

PROJECT SUMMARY/ABSTRACT SCA1 is a dominantly inherited neurodegenerative disease caused by expansion of CAG repeats in the ATAXIN-1 (ATXN1) gene. Patients with SCA1 suffer from progressive gait and balance deficits, and severe degeneration of Purkinje cells (PCs) in the cerebellar cortex and neurons in the cerebellar nuclei (CbN). There

are no effective disease modifying therapies currently available for SCA1, indicating a critical need for better understanding of disease pathogenesis. Cerebellar nuclei are a key part of the cerebellar network and the main information output from the cerebellum. As a consequence, CbN are relevant to motor behaviors regulated by the cerebellum. Remarkably, very little is

known about the dysfunction of CbN in any of the spinocerebellar ataxias (SCAs), including SCA1. The research described in this proposal will determine how CbN function is altered throughout SCA1 progression, how mutant ATXN1 (mATXN1) impacts the CbN, and how changes in CbN contribute to SCA1-like motor

deficits. An additional impact of this study will be to expand the concept of SCA1 as a cerebellar circuit dysfunction disease, stimulating future studies into interactions of the cerebellar cortex and CbN, not only in SCA1, but in other ataxias as well.