Abnormal Local Brain Activity in SCA3 Patients with Cognitive Impairment: A Resting-State Functional MRI Study

Area of Science:

• Neuroscience
• Radiology
• Genetics

Background:

• Cognitive impairment (CI) is a known feature of spinocerebellar ataxia 3 (SCA3).
• The relationship between intrinsic brain activity and cognitive dysfunction in SCA3 is not well understood.
• Elucidating these links is crucial for understanding SCA3's pathophysiology.

Purpose of the Study:

• To investigate alterations in intrinsic brain activity in SCA3 patients with cognitive impairment.
• To explore the association between these brain activity changes and cognitive functions.
• To provide imaging evidence for the mechanisms of cognitive decline in SCA3.

Main Methods:

• Resting-state functional magnetic resonance imaging (rs-fMRI) was used in 84 SCA3 patients and 41 healthy controls (HCs).
• rs-fMRI metrics including ALFF, fALFF, ReHo, and DC were analyzed.
• Patients were categorized into CI and non-CI groups; correlations between rs-fMRI metrics and cognitive scores were performed.

Main Results:

• SCA3 patients with CI exhibited altered intrinsic brain activity, including increased/decreased ALFF in specific regions (fronto-striatal, default mode network).
• Changes in fALFF, ReHo, and DC were observed in areas associated with cognitive function and the cortico-striato-thalamo-cortical loop.
• rs-fMRI metric alterations significantly correlated with cognitive performance in SCA3 patients.

Conclusions:

• Distinct patterns of spontaneous brain activity are associated with cognitive impairment in SCA3.
• These findings highlight the role of the cortico-striato-thalamo-cortical loop and cerebellar regions in SCA3-related cognitive decline.
• This study offers novel neuroimaging insights into the pathophysiological mechanisms of cognitive impairment in SCA3.