Dynamic topological changes of the motor network after stroke.

Area of Science:

• Neuroscience
• Systems Neuroscience
• Clinical Neurology

Background:

• Motor stroke impacts functional connectivity and topology of the motor system.
• Time-varying connectivity is crucial for motor impairment and recovery.
• The temporal dynamics of motor network topology after stroke remain largely unexplored.

Purpose of the Study:

• Identify dynamic central motor nodes associated with motor impairment post-stroke.
• Characterize dynamic interactions within the motor system using graph theory and dynamic functional connectivity MRI.
• Investigate the clinical relevance of temporal dynamics in motor network organization.

Main Methods:

• Utilized resting-state fMRI data from 20 acute stroke patients.
• Applied a sliding window approach to estimate dynamic functional connectivity within the motor network.
• Computed time-varying nodal betweenness centrality to identify dynamic central motor nodes and their association with upper limb impairment.

Main Results:

• Identified a dynamic central motor node in the ipsilesional anterior ventral central sulcus (vCS).
• Severely impaired patients showed shorter durations in high centrality mode compared to less impaired individuals.
• Upper limb impairment correlated with reduced functional connectivity between the vCS node and specific left hemisphere and cerebellar regions.

Conclusions:

• Acute motor stroke significantly affects the time-varying topological properties of motor network functional interactions.
• These dynamic topological changes are linked to upper limb impairment severity.
• Findings offer insights into the neural mechanisms underlying motor deficits after stroke.