Characterizing Differences in Functional Connectivity Between Posterior Cortical Atrophy and Semantic Dementia by...

Area of Science:

• Neuroscience
• Neurology
• Medical Imaging

Background:

• Posterior cortical atrophy (PCA) and semantic dementia (SD) are distinct focal neurodegenerative syndromes affecting specific brain regions.
• Understanding their underlying neural network dysfunction is crucial for diagnosis and treatment.

Purpose of the Study:

• To investigate and demonstrate abnormal functional connectivity (FC) within affected neural networks in patients with PCA and SD.
• To identify distinct and shared patterns of FC alterations between PCA and SD.
• To correlate observed FC changes with cognitive impairments.

Main Methods:

• Recruited 10 PCA patients, 12 SD patients, and 11 healthy controls for clinical assessment and PET/MRI scans.
• Conducted seed-based FC analyses on language, visual, and salience networks.
• Utilized two-sample t-tests to identify distinct FC patterns and correlated these with cognitive function.

Main Results:

• Both PCA and SD patients exhibited global cognitive impairment.
• PCA patients showed decreased FC in visual networks (e.g., left precentral gyrus to left V1) and altered FC in language and salience networks.
• SD patients displayed altered FC in language and salience networks, with some connections positively and others negatively correlating with cognitive function.

Conclusions:

• Abnormal functional connectivity in language and salience networks is common to both PCA and SD.
• FC alterations in the visual network appear unique to PCA.
• Observed FC changes in both conditions are closely associated with their respective cognitive deficits.