Brain Plasticity Mechanisms Underlying Motor Control Reorganization: Pilot Longitudinal Study on Post-Stroke Subjects

Area of Science:

• Neuroscience
• Rehabilitation Medicine
• Medical Imaging

Background:

• Functional Electrical Stimulation (FES) offers lasting improvements in walking ability (carryover effect).
• Chronic stroke patients often experience motor deficits, including foot drop, impacting mobility.
• Understanding the neural mechanisms behind FES-induced recovery is crucial for optimizing rehabilitation.

Purpose of the Study:

• To investigate brain connectivity changes in chronic stroke patients undergoing FES rehabilitation for foot drop.
• To differentiate neural responses between FES responders and non-responders regarding the carryover effect.
• To compare these changes with healthy controls using functional magnetic resonance imaging (fMRI).

Main Methods:

• Employed Bayesian hierarchical procedures with nonlinear (dynamic causal models) and linear models.
• Utilized fMRI to assess effective connectivity in sensorimotor cortices (M1, S1), SMA, and angular gyrus.
• Analyzed longitudinal changes in chronic stroke patients and compared them with a healthy control group.

Main Results:

• Reduced proprioception input sensitivity in the S1 area of FES non-responders suggests impaired motor planning and integration.
• Modulation of SMA and M1 connections to the S1 area indicates FES-related neural plasticity supporting active inference in motor control.
• The supplementary motor area (SMA) demonstrated a dual role in processing complex movements and modulating standard motor plans.

Conclusions:

• Proprioception integration and movement planning are key for the FES carryover effect.
• FES promotes neural plasticity consistent with active inference models of motor control.
• The SMA plays a critical role in adaptive motor control and complex movement execution.