Pectoral fin kinematics and motor patterns are shaped by fin ray mechanosensation during steady swimming in Scarus quoyi

For many species of fish, rhythmic movement of the pectoral fins, or forelimbs, drives locomotion. In terrestrial vertebrates, normal limb- based rhythmic gaits require ongoing modulation with limb mechanosensors. Given the complexity of the fluid environment and dexterity of fish swimming through it, we hypothesize that mechanosensory modulation is also critical to normal fin-based swimming. Here, we examined the role of sensory feedback from the pectoral fin rays and membrane on the neuromuscular control and kinematics of pectoral fin-based locomotion. Pectoral fin kinematics and electromyograms of the six major fin muscles of the parrotfish, Scarus quoyi, a high-performance pectoral fin swimmer, were recorded during steady swimming before and after bilateral transection of the sensory nerves extending into the rays and surrounding membrane. Alternating activity of antagonistic muscles was observed and drove the fin in a figure-of-eight fin stroke trajectory before and after ner...

对于许多鱼类而言，胸鳍（pectoral fins）或前肢的节律性运动驱动其移动。在陆生脊椎动物中，正常的基于肢体的节律性步态需要通过肢体机械传感器（mechanosensors）进行持续调节。鉴于流体环境的复杂性以及鱼类在其中游动的灵活性，我们假设机械传感调节（mechanosensory modulation）对正常的鳍式游动同样至关重要。在此，我们研究了胸鳍鳍条（pectoral fin rays）与膜的感觉反馈在胸鳍驱动运动的神经肌肉控制（neuromuscular control）及运动学（kinematics）中的作用。我们记录了鹦嘴鱼（Scarus quoyi）——一种高性能胸鳍游动鱼类——在稳定游动过程中的胸鳍运动学特征及六大主要鳍肌的肌电图（electromyograms），分别采集于双侧切断延伸至鳍条及周围膜的感觉神经之前与之后。观察到拮抗肌的交替活动，该活动在神经切断前后均驱动鳍呈现8字形划水轨迹...