Funding agencies: This work was supported in part by Universidad Nacional Autonoma de Mexico (PAPIIT IN202810 to Juan Fernandez-Ruiz); Consejo Nacional de Ciencia y Tecnologia (102314 to Juan Fernandez-Ruiz, 273115 to Carlos R. Hernandez-Castillo); and University of North Carolina-Chapel Hill startup fund (to Wei Gao).
Disruption of visual and motor connectivity in spinocerebellar ataxia type 7
Article first published online: 7 AUG 2013
© 2013 Movement Disorder Society
Volume 28, Issue 12, pages 1708–1716, October 2013
How to Cite
Hernandez-Castillo, C. R., Alcauter, S., Galvez, V., Barrios, F. A., Yescas, P., Ochoa, A., Garcia, L., Diaz, R., Gao, W. and Fernandez-Ruiz, J. (2013), Disruption of visual and motor connectivity in spinocerebellar ataxia type 7. Mov. Disord., 28: 1708–1716. doi: 10.1002/mds.25618
Relevant conflicts of interest/financial disclosures: Nothing to report.
Full financial disclosures and author roles may be found in the Acknowledgments section online.
- Issue published online: 25 OCT 2013
- Article first published online: 7 AUG 2013
- Manuscript Accepted: 1 JUL 2013
- Manuscript Revised: 28 JUN 2013
- Manuscript Received: 15 MAR 2013
- spinocerebellar ataxia 7;
- functional connectivity;
- visual network;
- motor network;
- frontocerebellar network
Spinocerebellar ataxia type 7 (SCA7) is an autosomal-dominant neurodegenerative disorder characterized by progressive ataxia and retinal dystrophy. It is caused by a CAG trinucleotide expansion in the ataxin7 gene. Anatomical studies have shown severe cerebellar degeneration and region-specific neocortical atrophy in SCA7 patients. However, the impact of the neurodegeneration on the functional integration of the remaining tissue is still unknown. The aim of this study was to examine functional connectivity abnormalities in areas with significant gray matter atrophy in SCA7 patients and their relationship with number of CAG repeats. Using a combination of voxel-based morphometry and resting-state fMRI, we studied 26 genetically confirmed SCA7 patients and aged-matched healthy controls. In SCA7 patients we found reduced functional interaction between the cerebellum and the middle and superior frontal gyri, disrupted functional connectivity between the visual and motor cortices, and increased functional coordination between atrophied areas of the cerebellum and a range of visual cortical areas compared with healthy controls. The degree of mutation expansion showed a negative effect on both the functional interaction between the right anterior cerebellum and the left superior frontal gyrus and the connectivity between the right anterior cerebellum and left parahippocampal gyrus. We found abnormal functional connectivity patterns, including both hypo- and hyperconnectivity, compared with controls. These abnormal patterns show reasonable association with the severity of gene mutation. Our findings suggest that aberrant changes are prevalent in both motor and visual systems, adding significantly to our understanding of the pathophysiology of SCA7. © 2013 International Parkinson and Movement Disorder Society