The objectives of this study are to investigate the contribution of sodium and calcium persistent inward currents (PICs) towards mediating the hyper-reflexia and motor control impairments seen in chronic spinal cord injury (SCI) using targeted pharmacological agents. This study will test the hypothesis that aberrant current activity in spinal motoneurons contributes to spastic hyper-reflexia following chronic spinal cord injury. Three specific aims are proposed to evaluate this hypothesis: