Department of Biology, University of Ottawa, 30 Marie-Curie Private, Ottawa, ON, Canada, K1N 6N5.
Department of Biology, Villanova University, 800 Lancaster Avenue, Villanova, PA 19085, USA.
J Exp Biol. 2023 May 1;226(9). doi: 10.1242/jeb.245192. Epub 2023 May 10.
Control of locomotion involves the interplay of sensory signals and motor commands. Sensory information is essential for adjusting locomotion in response to environmental changes. A previous study using mathematical modelling of lamprey swimming has shown that, in the absence of sensory feedback, increasing fluid viscosity constrains swimming kinematics, limiting tail amplitude and body wavelength, resulting in decreased swimming speed. In contrast, previous experiments with Polypterus senegalus reported increased magnitude swimming kinematics (increased body curvature, body wave speed and frequency, and pectoral fin frequency) in high viscosity water suggesting that sensory information is used to adjust swimming form. It is not known what sensory systems are providing the necessary information to respond to these environmental changes. We tested the hypothesis that lateral line and visual input are responsible for the sensory-driven increase in swimming kinematics in response to experimentally increased fluid viscosity. The kinematics of five P. senegalus were recorded in two different viscosities of water while removing lateral line and visual sensory feedback. Unlike the mathematical model devoid of sensory feedback, P. senegalus with lateral line and/or visual senses removed did not reduce the magnitude of swimming kinematic variables, suggesting that additional sensory feedback mechanisms are present in these fish to help overcome increased fluid viscosity. Increases in swimming speed when both lateral line and visual sensory feedback were removed suggest that lateral line and visual information may be used to regulate swimming speed in P. senegalus, possibly using an internal model of predictions to adjust swimming form.
运动控制涉及感觉信号和运动指令的相互作用。感觉信息对于根据环境变化调整运动至关重要。先前使用数学模型对七鳃鳗游泳的研究表明，在没有感觉反馈的情况下，增加流体粘度会限制游泳运动学，限制尾部幅度和身体波长，从而降低游泳速度。相比之下，先前对塞内加尔肺鱼的实验报告表明，在高粘度水中游泳运动学的幅度增加（增加身体曲率、身体波速度和频率以及胸鳍频率），表明感觉信息用于调整游泳形式。尚不清楚哪些感觉系统提供了响应这些环境变化所需的信息。我们测试了这样一个假设，即侧线和视觉输入负责对实验中增加的流体粘度做出反应，从而导致游泳运动学的感觉驱动增加。在两种不同粘度的水中记录了五条塞内加尔肺鱼的运动学，同时去除了侧线和视觉感觉反馈。与没有感觉反馈的数学模型不同，去除侧线和/或视觉感觉的塞内加尔肺鱼并没有降低游泳运动学变量的幅度，这表明这些鱼中存在额外的感觉反馈机制来帮助克服增加的流体粘度。当同时去除侧线和视觉感觉反馈时游泳速度的增加表明，侧线和视觉信息可能用于调节塞内加尔肺鱼的游泳速度，可能使用内部预测模型来调整游泳形式。
