Department of Biological Sciences, University of Alberta, Edmonton, AB, T6G 2E0, Canada.
Grass Laboratory, Marine Biological Laboratory, Woods Hole, MA, USA.
J Comp Physiol A Neuroethol Sens Neural Behav Physiol. 2024 Sep;210(5):801-814. doi: 10.1007/s00359-024-01694-6. Epub 2024 Mar 23.
For most quadrupeds, locomotion involves alternating movements of the fore- and hindlimbs. In birds, however, while walking generally involves alternating movements of the legs, to generate lift and thrust, the wings are moved synchronously with each other. Neural circuits in the spinal cord, referred to as central pattern generators (CPGs), are the source of the basic locomotor rhythms and patterns. Given the differences in the patterns of movement of the wings and legs, it is likely that the neuronal components and connectivity of the CPG that coordinates wing movements differ from those that coordinate leg movements. In this study, we used in vitro preparations of embryonic chicken spinal cords (E11-E14) to compare the neural responses of spinal CPGs that control and coordinate wing flapping with those that control alternating leg movements. We found that in response to N-methyl-D-aspartate (NMDA) or a combination of NMDA and serotonin (5-HT), the intact chicken spinal cord produced rhythmic outputs that were synchronous both bilaterally and between the wing and leg segments. Despite this, we found that this rhythmic output was disrupted by an antagonist of glycine receptors in the lumbosacral (legs), but not the brachial (wing) segments. Thus, our results provide evidence of differences between CPGs that control the wings and legs in the spinal cord of birds.
对于大多数四足动物来说，运动涉及前肢和后肢的交替运动。然而，在鸟类中，虽然行走通常涉及腿部的交替运动，但为了产生升力和推力，翅膀是同步移动的。脊髓中的神经回路，称为中枢模式发生器（CPG），是基本运动节律和模式的来源。鉴于翅膀和腿部运动模式的差异，协调翅膀运动的 CPG 的神经元成分和连接性可能与协调腿部运动的 CPG 不同。在这项研究中，我们使用了胚胎鸡脊髓（E11-E14）的体外培养物，比较了控制和协调翅膀拍打运动的脊髓 CPG 的神经反应与控制交替腿部运动的 CPG 的神经反应。我们发现，对 N-甲基-D-天冬氨酸（NMDA）或 NMDA 和 5-羟色胺（5-HT）的组合的反应中，完整的鸡脊髓产生了双侧和翅膀与腿部之间同步的节律性输出。尽管如此，我们发现这种节律性输出在腰骶部（腿部）的甘氨酸受体拮抗剂的作用下受到干扰，但在臂部（翅膀）节段不受干扰。因此，我们的结果提供了鸟类脊髓中控制翅膀和腿部的 CPG 之间存在差异的证据。
