Brain functional networks become more connected as amyotrophic lateral sclerosis progresses: a source level...

Area of Science:

• Neuroscience
• Medical Physics
• Systems Biology

Background:

• Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease.
• Understanding alterations in brain network topology during ALS progression is crucial for developing therapeutic strategies.

Purpose of the Study:

• To investigate the hypothesis that brain networks exhibit increased hyper-connectivity as amyotrophic lateral sclerosis (ALS) progresses.
• To characterize changes in brain network topology and centrality in ALS patients at different disease stages.

Main Methods:

• Magnetoencephalography (MEG) and MRI recordings were performed on 54 ALS patients (early and advanced stages) and 25 controls.
• Brain activity reconstruction and synchronization estimation using the phase lag index in classical frequency bands.
• Calculation of brain topological metrics: leaf fraction, degree divergence, degree correlation, and betweenness centrality.

Main Results:

• Brain networks in ALS patients demonstrated increased connectivity, scale-freeness, and disassortativity across all frequency bands as the disease advanced.
• No significant differences were observed in specific brain areas, suggesting a global network alteration.
• The observed modified brain topology in ALS patients was found to be sub-optimal compared to healthy controls.

Conclusions:

• Brain network topology undergoes significant changes during the progression of amyotrophic lateral sclerosis (ALS).
• The findings indicate a progressive hyper-connectivity and altered network organization in ALS, which is sub-optimal for brain function.