Disrupted cerebellar connectivity reduces whole-brain network efficiency in multiple system atrophy

Area of Science:

• Neuroscience
• Neurology
• Medical Imaging

Background:

• Multiple system atrophy of the cerebellar type (MSA-C) is a rare, sporadic neurodegenerative disease.
• White matter degeneration in the cerebellum and pons is a hallmark of MSA-C.
• The impact of this degeneration on brain network integrity and efficiency remains incompletely understood.

Purpose of the Study:

• To investigate the topological organization and network efficiency of structural brain networks in patients with MSA-C.
• To determine the relationship between white matter integrity, network efficiency, and clinical symptoms, specifically ataxia.

Main Methods:

• Diffusion tensor tractography (DTT) was employed to construct structural brain networks.
• Graph theory analysis was utilized to assess network properties, including small-world architecture and topological organization.
• Nineteen patients with MSA-C were compared with 19 age- and sex-matched healthy controls.

Main Results:

• Patients with MSA-C exhibited significantly altered small-world network architecture, characterized by increased shortest path lengths and decreased clustering coefficients.
• White matter degeneration in the cerebellum led to reduced network strength and impaired network efficiency in connected cerebral regions.
• Decreased nodal efficiency in cerebellar, sensorimotor, prefrontal, and basal ganglia regions correlated negatively with ataxia severity.

Conclusions:

• This study provides the first structural evidence of disrupted white matter network topology in MSA-C.
• Abnormalities in white matter integrity and network efficiency are key features of MSA-C.
• The findings highlight the link between structural network disruptions and motor deficits in cerebellar MSA.