McClellan A D
Department of Physiology and Biophysics, University of Iowa, Iowa City 52242.
Brain Res. 1988 May 17;448(2):339-45. doi: 10.1016/0006-8993(88)91273-5.
Lower vertebrates can recover locomotor function after spinal transections, and several classes of neurons in these animals can regenerate. However, no studies have directly tested for functional regeneration of descending command pathways for the initiation of locomotion in the absence of complications from sensory feedback. In the present study, the contribution of regeneration of descending command pathways to the reacquisition of locomotion was examined in behaviorally recovered, spinal-transected larval lampreys using in vitro brain/spinal cord preparations, in which mechanosensory feedback was eliminated. Activation of brainstem command centers produced locomotor activity below a healed transection site and this burst activity was coupled 1:1 with locomotor activity above the transection site. Furthermore, the parameters characterizing locomotor patterns in in vitro preparations were similar to those recorded during locomotion in normal, whole-animals. Additional experiments indicated that descending pathways from the brainstem had regenerated across the healed transection site and could directly activate spinal locomotor networks below the lesion area. These data appear to be the first direct demonstration in a vertebrate of functional regeneration of descending command pathways for the initiation of locomotion.
低等脊椎动物在脊髓横断后能够恢复运动功能，并且这些动物中的几类神经元可以再生。然而，尚无研究在没有感觉反馈并发症的情况下直接测试用于启动运动的下行指令通路的功能再生。在本研究中，使用体外脑/脊髓制剂，在行为恢复的脊髓横断幼体七鳃鳗中，研究了下行指令通路再生对运动重新获得的贡献，其中消除了机械感觉反馈。脑干指令中心的激活在愈合的横断部位下方产生运动活动，并且这种爆发活动与横断部位上方的运动活动以1:1的比例耦合。此外，体外制剂中表征运动模式的参数与正常全动物运动期间记录的参数相似。额外的实验表明，来自脑干的下行通路已经在愈合的横断部位再生，并且可以直接激活损伤区域下方的脊髓运动网络。这些数据似乎是脊椎动物中首次直接证明用于启动运动的下行指令通路的功能再生。
