Human Lumbosacral Spinal Cord Interprets Loading During Stepping

Harkema, Susan J., Seanna L. Hurley, Uday K. Patel, Philip S. Requejo, Bruce H. Dobkin, and V. Reggie Edgerton. Human lumbosacral spinal cord interprets loading during stepping. J. Neurophysiol. 77: 797–811, 1997. Studies suggest that the human lumbosacral spinal cord can generate steplike oscillating electromyographic (EMG) patterns, but it remains unclear to what degree these efferent patterns depend on the phasic peripheral sensory information associated with bilateral limb movements and loading. We examined the role of sensory information related to lower-extremity weight bearing in modulating the efferent motor patterns of spinal-cord-injured (SCI) subjects during manually assisted stepping on a treadmill. Four nonambulatory subjects, each with a chronic thoracic spinal cord injury, and two nondisabled subjects were studied. The level of loading, EMG patterns, and kinematics of the lower limbs were studied during manually assisted or unassisted stepping on a treadmill with body weight support. The re...