Sensory Reweighting Revealed by Superior Parietal Cortex-Based Functional Connectivity in Chronic Ankle Instability:...

Area of Science:

• Neuroscience
• Biomechanics
• Human Motor Control

Background:

• Chronic ankle instability (CAI) is associated with impaired somatosensory function, leading to a presumed increased reliance on visual input for postural control.
• The precise neural mechanisms driving this sensory reweighting in CAI remain incompletely understood.

Purpose of the Study:

• To investigate the neural and behavioral correlates of heightened visual reliance in individuals with CAI.
• To explore functional connectivity (FC) patterns in the brain associated with sensory reweighting in CAI.

Main Methods:

• A cross-sectional study involving 37 CAI patients and 36 healthy controls.
• Postural stability assessed via single-leg stance tests (eyes open/closed) to calculate Romberg ratios.
• Resting-state functional MRI (fMRI) used to analyze FC between the superior parietal cortex (SPC) and visual, sensorimotor, and cerebellar regions.

Main Results:

• CAI patients exhibited significantly greater visual reliance compared to controls, evidenced by sway length Romberg ratios.
• Stronger FC was observed between the SPC and visual cortices in CAI patients.
• Increased variability in FC between the SPC and the cerebellar anterior lobe was noted in CAI patients.

Conclusions:

• CAI is characterized by significant visual reliance, driven by neural alterations in sensory reweighting.
• Altered functional connectivity, including strong but variable SPC-visual cortex links and variable SPC-cerebellar connections, underlies this increased visual dependency in CAI.