Department of Biology, University of Oklahoma, 730 Van Vleet Oval, Norman, OK 73019, USA.
J Comp Physiol A Neuroethol Sens Neural Behav Physiol. 2012 Dec;198(12):877-89. doi: 10.1007/s00359-012-0758-6. Epub 2012 Sep 18.
The spinal cord can generate motor patterns underlying several kinds of limb movements. Many spinal interneurons are multifunctional, contributing to multiple limb movements, but others are specialized. It is unclear whether anatomical distributions of activated neurons differ for different limb movements. We examined distributions of activated neurons for locomotion and scratching using an activity-dependent dye. Adult turtles were stimulated to generate repeatedly forward swimming, rostral scratching, pocket scratching, or caudal scratching motor patterns, while sulforhodamine 101 was applied to the spinal cord. Sulforhodamine-labeled neurons were widely distributed rostrocaudally, dorsoventrally, and mediolaterally after each motor pattern, concentrated bilaterally in the deep dorsal horn, the lateral intermediate zone, and the dorsal to middle ventral horn. Labeled neurons were common in all hindlimb enlargement segments and the pre-enlargement segment following swimming and scratching, but a significantly higher percentage were in the rostral segments following swimming than rostral scratching. These findings suggest that largely the same spinal regions are activated during swimming and scratching, but there are some differences that may indicate locations of behaviorally specialized neurons. Finally, the substantial inter-animal variability following a single kind of motor pattern may indicate that essentially the same motor output is generated by anatomically variable networks.
脊髓可以产生多种肢体运动的运动模式。许多脊髓中间神经元具有多功能性，可参与多种肢体运动，但其他中间神经元具有特异性。目前尚不清楚不同肢体运动激活的神经元的解剖分布是否不同。我们使用活性依赖性染料检查了运动和抓挠时激活神经元的分布。成年海龟被刺激以产生反复的向前游泳、头侧抓挠、口袋抓挠或尾侧抓挠运动模式，同时将 sulforhodamine 101 应用于脊髓。在每种运动模式后，sulforhodamine 标记的神经元在脊髓的头侧到尾侧、背侧到腹侧以及中间到外侧广泛分布，在双侧深背角、外侧中间区和背侧到中间腹侧集中分布。标记的神经元在游泳和抓挠后的所有后肢放大节段和前放大节段中都很常见，但游泳后的头侧节段比头侧抓挠中的头侧节段更高。这些发现表明，在游泳和抓挠过程中，脊髓的大部分区域被激活，但存在一些差异，这些差异可能表明存在行为特异性神经元的位置。最后，单一运动模式后动物之间的大量变异性可能表明，基本上相同的运动输出是由解剖结构不同的网络产生的。
