Sensory and motor cortex function contributes to symptom severity in spinocerebellar ataxia type 6

Nyeonju Kang, Evangelos A. Christou, Roxana G. Burciu, Jae Woo Chung, Jesse C. DeSimone, Edward Ofori, Tetsuo Ashizawa, Sankarasubramon H. Subramony, David E. Vaillancourt

Research output: Contribution to journalArticle

3 Scopus citations

Abstract

Spinocerebellar ataxia type 6 (SCA6) is a genetic disease that causes degeneration of Purkinje cells, and recent evidence points to degeneration of Betz cells in the motor cortex. The relation between functional activity of motor cortex and symptom severity during a hand-grip motor control in vivo has not yet been investigated. This study explored both functional changes in the sensorimotor cortex and cerebellar regions and structural alterations in the cerebellum for SCA6 patients as compared to age-matched healthy controls using a multimodal imaging approach (task-based fMRI, task-based functional connectivity, and free-water diffusion MRI). Further, we tested their relation with the severity of ataxia symptoms. SCA6 patients had reduced functional activity in the sensorimotor cortex, supplementary motor area (SMA), cerebellar vermis, and cerebellar lobules I-VI (corrected P < 0.05). Reduced task-based functional connectivity between cortical motor regions (i.e., primary motor cortex and SMA) and cerebellar regions (i.e., vermis and lobules I–VI) was found in SCA6 (corrected P < 0.05). SCA6 had elevated free-water values throughout the cerebellum as compared with controls (corrected P < 0.05). Importantly, reduced functional activity in the sensorimotor cortex and SMA and increased free-water in the superior cerebellar peduncle and cerebellar lobule V were related to more severe symptoms in SCA6 (all pairs: R2 ≥ 0.4 and corrected P < 0.05). Current results demonstrate that impaired functional activity in sensorimotor cortex and SMA and elevated free-water of lobule V and superior cerebellar peduncle are both related to symptom severity, and may provide candidate biomarkers for SCA6.

Original languageEnglish (US)
Pages (from-to)1039-1052
Number of pages14
JournalBrain Structure and Function
Volume222
Issue number2
DOIs
StatePublished - Mar 1 2017
Externally publishedYes

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Keywords

  • Diffusion MRI
  • Free-water
  • Functional MRI
  • Spinocerebellar ataxia type 6
  • Task-based functional connectivity

ASJC Scopus subject areas

  • Anatomy
  • Neuroscience(all)
  • Histology

Cite this

Kang, N., Christou, E. A., Burciu, R. G., Chung, J. W., DeSimone, J. C., Ofori, E., Ashizawa, T., Subramony, S. H., & Vaillancourt, D. E. (2017). Sensory and motor cortex function contributes to symptom severity in spinocerebellar ataxia type 6. Brain Structure and Function, 222(2), 1039-1052. https://doi.org/10.1007/s00429-016-1263-4