| Neuroscience/ Translational neurology | Rare Neurological Diseases  

Cerebello-Prefrontal Connectivity in Spinocerebellar Ataxia Type 2

This study by Kumar et al. explores the neural circuits underlying cognitive dysfunction in spinocerebellar ataxia type 2 (SCA2), an inherited neurodegenerative disorder previously recognized primarily for its motor symptoms. Using a cerebello-cortical EEG technique, the authors investigated resting-state functional connectivity between the cerebellum and prefrontal cortex in SCA2 patients compared to healthy controls. They found that SCA2 patients showed altered source-space spectral analysis in the cerebellum, with significant changes in delta, theta, and beta frequencies.

Spinocerebellar ataxia type 2 (SCA2) is a hereditary neurodegenerative disorder that primarily affects the cerebellum, resulting in both motor and cognitive symptoms. The cognitive impairments associated with this condition, known as cerebellar cognitive affective syndrome (CCAS), significantly impact patients' quality of life. The specific brain circuits involved in the cognitive dysfunction seen in SCA2 remain poorly understood. This study by Kumar et al (1) included 12 SCA2 patients and 24 age-matched controls. The researchers used EEG to examining connectivity across different frequency bands in cerebellum and cortex, and correlating these findings with cognitive dysfunction as measured by CCAS scores.

Their main result is that SCA2 patients exhibited decreased theta connectivity and increased beta connectivity between the posterior cerebellum and the prefrontal cortex. No significant differences were observed in delta connectivity. Notably, the increased beta connectivity was specific to the prefrontal regions and was not found in other cortical areas. Furthermore, higher beta connectivity correlated with poorer cognitive performance on CCAS scores, suggesting a direct link between altered cerebello-prefrontal communication and cognitive dysfunction in SCA2. These findings emphasize the importance of the cerebello-prefrontal circuit in cognitive function and its disruption in SCA2.

Key Points:

  • Spinocerebellar ataxia type 2 is not only a motor disorder but also features prominent cognitive symptoms known as cerebellar cognitive affective syndrome.
  • Resting-state connectivity assessed through EEG can be used for investigating whole-brain circuit mechanisms related to various neuropsychiatric disorders.
  • In the present study they found increased beta connectivity between the cerebellum and prefrontal regions, which correlated with the severity of cognitive dysfunction in the patients.

References:

  1. Kumar, Ami, et al. "Cerebello‐Prefrontal Connectivity Underlying Cognitive Dysfunction in Spinocerebellar Ataxia Type 2." Annals of Clinical and Translational Neurology.

Publish on behalf of the Coordinating Panel on Neuroscience/ Translational Neurology

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