Microstructural properties of premotor pathways predict visuomotor performance in chronic stroke

Area of Science:

• Neuroscience
• Motor Control
• Neuroimaging

Background:

• Corticospinal tract (CST) microstructure impacts motor function post-stroke.
• The relationship between brain structure and visuomotor processing after stroke is not well understood.

Purpose of the Study:

• To investigate the link between CST microstructure and visuomotor control in individuals post-stroke.
• To determine if CST microstructural properties predict force variability changes with visual gain.

Main Methods:

• Diffusion MRI and probabilistic tractography were used to analyze primary and premotor CSTs.
• Participants performed a unimanual force task at varying visual gain levels.
• Fractional anisotropy (FA) was measured within CSTs to predict force variability.

Main Results:

• Individuals post-stroke exhibited greater force variability than controls and reduced variability with increased visual gain.
• Lower FA was observed in the primary motor and premotor CSTs of individuals post-stroke.
• Premotor CST FA, not primary motor CST FA, best predicted force variability.

Conclusions:

• Premotor CST microstructure is a key predictor of visual gain-related force variability adjustments post-stroke.
• These findings highlight the role of premotor pathways in visuomotor adaptation after stroke.