Abstract: Aspinal cord over-hemisection model was reproduced using a sterotaxic and electro-magnet-controlled pincher for spinal injury.The locomotion of paralyzed hindlimb was observed in this model and its possible mechanisms were analysed.Our results showed that the ipsliateral hindilmb paralyzed transiently and gradually restituted its coordinative locomotion and weight-bearing about one week after spinal cord injury.When the spinal cord was sec- tioned longitudinally along its central line from L₃～L₆,the locomotion in contralateral hindlimb remained.When second over-hemisection was made contralaterally to the first one, both the hindlimb's locomotion disappeared.The results indicate that there are segmental interconnections between left and right central pattern generator(CPG)or spinal locomotion generator(SLG),which may related closely to spinal reflex center.Under the condition of completely losing descending control in one side,CPGs of SLGs in this side can still be activated and basically play their role in controlling the ipsilateral hindlimb's locomotion,possibly by the involvement of descending innervation and/or CPGor SLGat segmental level from the contralateral side.

Key words: spinal cord hemisection, coordinate locomotion, spinal locomotion generator, central patern generator, plasticity