Divergent brain network connectivity in amyotrophic lateral sclerosis

Area of Science:

• Neuroscience
• Neurology
• Cognitive Science

Background:

• Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease.
• Cognitive impairment is common in ALS, but overt dementia is not always present.
• Understanding brain network alterations in non-demented ALS patients is crucial.

Purpose of the Study:

• To investigate the integrity of brain networks related to cognition and behavior in non-demented ALS patients.
• To assess the association between resting-state functional connectivity and executive functions in ALS.
• To identify potential compensatory mechanisms in the ALS brain.

Main Methods:

• Resting-state functional magnetic resonance imaging (RS-fMRI) was employed.
• Independent component analysis (ICA) was used to analyze brain networks.
• Neuropsychological assessments were conducted to evaluate executive functions.

Main Results:

• ALS patients exhibited decreased connectivity in the right orbitofrontal cortex (default mode network) and left inferior frontal cortex (right frontoparietal network).
• Increased connectivity was observed in the left precuneus (default mode network), right angular gyrus (right frontoparietal network), and parietal cortex (left frontoparietal network).
• Enhanced parietal connectivity correlated with clinical and cognitive deficits in ALS patients.

Conclusions:

• Functional brain network alterations associated with cognition occur in ALS, irrespective of overt dementia.
• Increased parietal connectivity might represent a compensatory mechanism to maintain cognitive function despite frontotemporal injury.
• These findings highlight the complex neural adaptations in ALS and their relationship to cognitive status.