Absence of local sign withdrawal in chronic human spinal cord injury.

摘要: Local sign withdrawal, a reflex to direct the limb away from noxious cutaneous stimuli, is thought be indicative of modular organization spinal cord. To assess integrity such an cord in chronic human injury (SCI), we tested electromyogram (EMG) and joint torque responses stimuli applied 6 locations leg 10 SCI volunteers 3 spinal-intact controls. The included medial arch foot, second metatarsal, dorsum, region over sural nerve at lateral malleolus, anterior posterior aspects lower leg. Although subjects demonstrated local data indicated that invariant flexion response pattern was produced regardless stimulus location. Ankle dorsiflexion hip were all no difference ratio hip:ankle torques could detected for test locations. A windup-crossover test, employing sequence 1-s intervals used whether common neuronal pathways responsible loss organization. An additional using which location switched between 2nd 3rd sequence. crossover more closely resembled windup than without conditioning stimuli. These results indicate increased excitability by one site maintained site. This observation suggests deep dorsal horn neurons, typically associated with musculotopic mapping, may reorganized injury.