Executive dysfunction relates to salience network desegregation in behavioural variant frontotemporal dementia

Area of Science:

• Neuroscience
• Cognitive Neurology
• Neuroimaging

Background:

• Brain network organization differentiates during development and de-differentiates with aging.
• Behavioral variant frontotemporal degeneration (bvFTD) is characterized by executive dysfunction and salience network vulnerability.
• Network de-differentiation is linked to cognitive decline in healthy aging.

Purpose of the Study:

• To test if bvFTD patients show reduced brain network differentiation compared to controls.
• To investigate the association between network de-differentiation and executive function in bvFTD.

Main Methods:

• Diffusion MRI and probabilistic tractography were used to generate network maps.
• System segregation was calculated to quantify network differentiation.
• Executive function was assessed using neuropsychological tests in 90 bvFTD patients and 71 controls.

Main Results:

• bvFTD patients exhibited significantly lower system segregation in the salience and global brain networks compared to controls.
• Reduced salience network segregation in bvFTD was associated with poorer executive function.
• No association was found between salience network segregation and lexical retrieval.

Conclusions:

• Executive dysfunction in bvFTD is associated with de-differentiation of the salience network.
• Reduced neural capacity for specialized processing may underlie executive dysfunction in bvFTD.
• Brain network de-differentiation is a potential mechanism contributing to bvFTD-related cognitive deficits.