Cortical dynamics associated with adaptive increases in clearance after obstacle contact

This study aimed to investigate motor adaptation following obstacle contact and the underlying neural control mechanisms. 25 healthy young adults were recruited to perform an obstacle-crossing walking task, and 17 participants were included in the analysis. The gait cycle was divided into three phases: approach (the step immediately before obstacle crossing), lead (when the lead limb crosses the obstacle), and trail (when the trail limb crosses the obstacle). Power in the theta, alpha, and beta bands was calculated at electrode sites Fz, Cz, and Pz for each phase, while vertical clearance of the lead and trail limbs and horizontal distance from the obstacle were assessed as kinematic measures. Electroencephalography (EEG) and kinematic variables were compared between the 30 trials before and after obstacle contact (pre- and post-conditions). Vertical clearance of both lead and trail limbs increased significantly after obstacle contact (post-condition). In addition, theta power at Fz significantly increased during the approach phase, and the magnitude of this increase was significantly correlated with the increase in trail clearance. Beta power at Cz significantly decreased during the lead phase, but the magnitude of this change was not significantly correlated with changes in clearance. In contrast, no significant changes in EEG power were observed during the trail phase. These findings suggest that increased involvement of the frontal and motor cortices contributes to the adaptive changes following obstacle contact. Furthermore, although clearance increased in both lead and trail limbs, the underlying neural control mechanisms may differ.