Enhanced positive functional connectivity strength in left-sided chronic subcortical stroke

Area of Science:

• Neuroscience
• Neurology
• Neuroimaging

Background:

• Stroke survivors often show abnormal functional connectivity (FC).
• The impact of anatomical distance on resting-state FC in chronic subcortical stroke is not well understood.

Purpose of the Study:

• To investigate the effect of anatomical distance on functional connectivity strength (FCS) in patients with chronic subcortical stroke.
• To explore the relationship between FCS alterations and cognitive function in stroke survivors.

Main Methods:

• Resting-state functional magnetic resonance imaging (fMRI) was used in 86 chronic subcortical stroke patients and 75 healthy controls.
• A data-driven whole-brain method computed positive functional connectivity strength (FCS), divided into short- and long-range.
• Cognitive function was assessed using the Flanker test.

Main Results:

• Patients with left-sided strokes showed significantly stronger global and long-range FCS in the left sensorimotor cortex (SMC) compared to controls.
• No significant differences in short-range FCS were observed between left-sided stroke patients and controls.
• No significant differences in global, long-, or short-range FCS were found between right-sided stroke patients and controls.

Conclusions:

• Altered positive FCS in chronic left-sided subcortical stroke is dependent on connection distance.
• Stronger long-range FCS in the left SMC correlates with better performance on the Flanker test, suggesting a compensatory mechanism for attention and executive function deficits.