A SYSTEMATIC APPROXIMATION TO THE NEURAL MOTOR CONTROL OF FORWARD, BACKWARD AND LATERAL TOE-TAPPING IN CHILDREN AND ADULTS

Abstract

The neural motor control of forward, backward and lateral toe-tapping of typically developing adults, 6- and 10-year-old children was investigated using the uncontrolled manifold technique. Our results indicate that the central nervous system (CNS) controls or stabilizes three functional variables (center of mass, toe and head position) by organizing the overall joint variability structure, more than the individual joints. Results reveal: (1) children control forward and backward stepping more than adults, and (2) adults' forward stepping is more controlled than backward or lateral stepping. The relative ranking defining the approximate neural motor control of toe-tapping is: center of mass, toe and head position; indicating the CNS focuses on balance and foot placement. The observed invariance of this structure across movement phase, tap direction, and age, reinforces the idea that the CNS controls multi-directional toe-tap motion using similar neural control strategy.