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Supplementary Material for Lutek, Foster and Standen (2022 JEB) Behaviour and muscle activity across the aquatic-terrestrial transition in Polypterus senegalus
No full textSupplementary code for statistics performed in Keegan Lutek, Kathleen L. Foster, Emily M. Standen; Behaviour and muscle activity across the aquatic-terrestrial transition in Polypterus senegalus. J Exp Biol 2022; jeb.243902. doi: https://doi.org/10.1242/jeb.243902. All files are located here and the readme.txt will guide you as to how to use the data and code to replicate the analysis
Supplementary Material for Lutek et al 2022 JEB
No full textSupplemental Material - Patterns and processes in fish terrestrial biomechanics: Biomechanics and neural control of fish terrestrial locomotion
This repository contains the r-code (LutekEtAl_SupCode.rmd) and data file (actinopt_12k_treePL.tre) to run the analysis and generate the figures used in the above paper. You will also need the supplemental Material file uploaded to JEB (TableS1_PhylogenyData.xlsx) to run the code.
NOTE that actinopt_12k_treePL.tre was downloaded from The Fish Tree of Life website (https://fishtreeoflife.org/downloads/). For more information about this tree, please visit their website (https://fishtreeoflife.org/about/).
TO RUN CODE
Please be sure that "Table1_PhylogenyData.xlsx" and "actinopt_12k_treePL.tre" are in the same file folder as LutekEtAl_SupCode.rmd before opening the r-notebook
Replication data for: Liang et al 2025. Walking elicits muscle functional changes in the pectoral fin of Polypterus senegalus. JEB
No full textThis dataset contains all numerical data (electromyogrpahy and kinematics) and r-code required to replicate the analysis discussed in Liang et al. 2025. Walking elicits muscle functional change in the pectoral fin of Polypterus senegalus. doi:10.1242/jeb.250474.
The r-code (Liang_etal_2025_RProject.Rproj and tidyLinearAnalysis.R) works in conjunction with the three csv files in the accompanying tidyDataFiles folder. TO RUN CODE please ensure that the tidyDataFiles folder is in the same directory as the r-code files for proper functioning
Sensory Capabilities of Polypterus Senegalus in Aquatic and Terrestrial Environments
No full textIn the amphibious fish Polypterus senegalus, focussing on lateral line, vision and electrosensation, we investigated sensory abilities, their interactions, and changes in their effects on locomotor behaviour between aquatic and terrestrial environments. First, we blocked lateral line, vision, or both, and examined effects on locomotion in both environments. Both senses affected both types of locomotion. When fish could see but not feel, variation in several kinematic variables increased, suggesting that sensory integration may affect locomotor control. Next, we assessed response to optokinetic stimuli of varying size and speed. Temporal and spatial visual acuity were both low, as expected in a nocturnal ambush predator. Visual ability in air was much reduced. Finally, we attempted to record electrogenesis in Polypterus, but did not observe the electric discharges reported in a previous study. Future studies might examine changes in sensory function, interaction and importance in behaviour in Polypterus raised in a terrestrial environment
Locomotor Plasticity of an Amphibious Fish (Polypterus senegalus)
No full textAnimals control locomotion through unpredictable and complex habitats using a single locomotor control system. Because of the disparate physical mechanics of different environments, behavioural plasticity, based on the complex interplay of sensory feedback and environmental constraints, is likely essential for animals moving across environments. However, few studies have investigated neuromuscular control across different environments. To fill this gap, I make use of Polypterus senegalus to address four primary objectives: (1) to explore the extent of neuromuscular plasticity across environmental gradients (viscosity and water depth), (2) to generate and test hypotheses about paramount signals for this neuromuscular plasticity, (3) to determine the neuromuscular underpinnings of locomotor transitions, and (4) to determine the neuromuscular control of developmental behavioural plasticity in novel environments. I measured the kinematic and muscle activity response of P. senegalus to gradual changes in environment forces using gradients of water viscosity and water depth. I then used a semi-intact preparation to investigate the existence and role of the mesencephalic locomotor region, a brain region that controls locomotor speed and mode in other species, for neuromuscular control in P. senegalus. Finally, I used chronic terrestrial acclimation and exercise to determine the neuromuscular underpinnings of behavioural and morphological plasticity previously seen in P. senegalus reared in a terrestrial environment. I found that in high viscosity environments, P. senegalus maintain routine swimming speed using a swimming-like muscle activity pattern with increased effort in the posterior body and the pectoral fin to generate exaggerated swimming kinematics. These results suggest that sensory feedback is essential to accommodating this novel environment. I then demonstrated that axial red muscle always carried an anterior-to-posterior wave of muscle activity in a series of discrete water depths across the aquatic-terrestrial transition. Thus, discrete changes in axial kinematics and pectoral fin coordination across this transtion are likely the result of sensory feedback and mechanical constraints of the environment. I then performed the first experiments searching for the mesencephalic locomotor region in P. senegalus and demonstrated the presence of a putative mesencephalic locomotor region that controls the frequency of swimming-like movements but does not appear to control pectoral fin movements or the transition to walking. Finally, I exposed P. senegalus to chronic terrestrial acclimation and exercise. My results suggested that while both terrestrial acclimation and exercise generate behavioural plasticity, the former results in a larger plastic repsonse. Subtle changes in the duration and timing of pectoral fin muscle activity helped reduce friction between the body and pectoral fin and the substrate below, potentially resulting in the more “effective” walking gait developed by terrestrial acclimated fish. My thesis therefore sheds light on the essential interplay of sensory feedback and mechanical constraint for generating behavioural plasticity on acute and chronic timescales, highlights the potential value of such plasticity for organismal performance and evolution, and develops study systems and experimental frameworks for further investigating the nature of plastic locomotor control in amphibious fish
A First Look: Understanding the Ground Reaction Forces Experienced by Pectoral Fins of Polypterus Senegalus During Terrestrial Locomotion
No full textPolypterus senegalus, an extant member of the ray-finned fishes, can both swim in water and walk overland. Both environments impose different locomotor requirements on Polypterus fins. In an aquatic environment, forward propulsion is largely generated through oscillations of the pectoral fins working in sync with each other. On land, the pectoral fins are engaged in a contralateral gait, and are involved in lifting the body off the ground while simultaneously balancing the body. Polypterus have been shown to undergo behavioural, anatomical, and physiological changes during both short- and long-term exposure to land. Differences in force environments and locomotor behaviour between aquatic and terrestrial environments are hypothesized to be the cause of these plastic changes observed in the musculoskeletal tissues of Polypterus. Despite these observable changes, it is unclear exactly how the pectoral fins are experiencing ground reaction forces (GRF) during terrestrial locomotion. By measuring and quantifying force production during walking in Polypterus, this thesis provides a first look at the relationship between GRFs produced and experienced during walking and the pectoral fins of the amphibious fish, Polypterus. The kinematics of the pectoral fins and fore body were analyzed during terrestrial locomotion, and strategic points across both pectoral fins and body were digitized. Kinematics were compared with GRFs in the thrust (X), stabilizing (Y) and lifting (Z) planes to understand how impact forces travel through the fin tissues. Further analysis, using inverse dynamics, is required to determine how these impact forces travel through the musculature of the pectoral fins, perhaps providing potential hypotheses as to the effects of GRFs and their role in not only how terrestrial locomotion affects the behavioural, anatomical, and physiological plasticity observed in Polypterus, but also the limbs of tetrapods during the evolutionary transition from aquatic to terrestrial environments
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