Brain Topological Reorganization Associated with Visual Neglect After Stroke

Area of Science:

• Neuroscience
• Cognitive Neuroscience
• Neuroimaging

Background:

• Spatial neglect is a common and disabling deficit following stroke, particularly right hemisphere damage.
• Understanding the neural underpinnings of neglect is crucial for developing effective rehabilitation strategies.

Purpose of the Study:

• To identify brain hubs behaviorally relevant for spatial neglect after stroke.
• To characterize the functional communication architecture of these neglect hubs.

Main Methods:

• Resting-state functional magnetic resonance imaging (rs-fMRI) and neuropsychological assessments were conducted on 20 acute right hemisphere stroke patients.
• Betweenness centrality (BC) was calculated for 153 brain nodes to identify hubs correlating with neglect severity.
• Weighted shortest path length (WSPL) was analyzed to assess network efficiency.

Main Results:

• Neglect hubs in the damaged hemisphere (attention, default mode, executive control networks) showed decreased BC and increased WSPL, indicating reduced efficiency.
• Neglect hubs in the undamaged hemisphere (visual, motor networks) exhibited increased BC and reduced WSPL, suggesting compensatory hyperactivity.
• These topological changes correlated with neglect severity.

Conclusions:

• Brain reorganization in neglect involves a shift from higher-level associative systems to lower-level sensory-motor areas.
• This topological reorganization may represent a maladaptive strategy for processing spatial information post-stroke.
• Identifying these neglect hubs offers potential targets for therapeutic interventions.