A comparative study of axial neuromuscular control in Polypterus senegalus: Is walking really novel? Misha Dhuper, Dr. Kathleen Foster, Dr. Emily Standen Department of Biology, University of Ottawa

BACKGROUND METHODS CONCLUSIONS

Digitized 6 • There is a progression of activity from Inserted points along electrodes body on anterior to posterior on both sides of during fish videos via the fish both when swimming and surgery Matlab walking. Collected software 3D video and • Contralateral matching pairs of points EMG outputs have their muscle activity happening

Wilhelm et al, 2015 on opposite sides of the polar plot (i.e. approx. 180° later in the stroke cycle). • Polypterus senegalus possesses • Muscle activity, including max activity behavioural and anatomical plasticity happens later in the stroke cycle when when raised in a terrestrial walking than when swimming. environment. • Swimming speed is significantly faster • Many features make them of particular than walking speed. interest in examining transitions from • Muscles are working harder (increased water to land including: a paired lung, effort over a longer period of time and lobed pectoral limbs, ability to breathe with greater electrical amplitude) through their spiracle as well as during walking than in swimming in observed terrestrial excursions both in RESULTS body points that are closer to the front the wild and in the laboratory. A D of the body. • Member of the most basal extant clade of Actinopterygii. • Adds to the knowledge of the evolution of the anatomy of Osteichthyes. Onset FUTURE DIRECTIONS time

• Investigate muscle activation patterns INTRODUCTION in fish raised on land for an extended period of time. B E • We predict that fish raised on land will • Aquatically raised fish were used. have different body muscle activation • Hypothesized that in the short term, patterns during walking compared with neuromuscular activation patterns in those raised in water. body muscle would be co-opted from Offset • Explore the red and white muscle existing behaviours, thus, walking time phenomenon observed during the behaviour should be more similar to study. what is seen in escape responses • Determine mechanical effectiveness of rather than routine swimming and differences in muscle activation and should require more effort. muscle length change measurements • Data was collected during the study (sonomicrometry) . using high-speed videography, camera C F calibration, and video and motion analysis in Matlab. • By examining the similarities and Time of differences between the ACKNOWLEDGEMENTS neuromuscular controls of different max amp behaviours, it can be determined if and I would like to thank Dr. Emily Standen for her how the systems that dictate the guidance through the course of this project and for “novel” walking behaviour are adjusted giving me the opportunity to participate in UROP. Special thanks to everyone in the Standen Lab for all from the control mechanisms the fish Figure ABC. Muscle activation timing their support, especially those in Team Body Wave: Dr. would regularly use. in swimming and walking fish. A Kathleen Foster, David, and Ashley. shows the first muscle burst onset time. 1. Standen, E.M., Du, T. Y., and Larsson, H.C. E. (2014), B shows the first muscle burst offset Figure DEF. D shows swimming speed is Developmental plasticity and the origin of tetrapods. Nature, time. C depicts the time of maximum significantly faster than walking. E and F 4;513(7516):54-8. doi: 10.1038/nature13708 2. Wilhelm, B. C., Du, T. Y., Standen, E. M. and Larsson, H. C. Misha Dhuper [email protected] burst amplitude. indicate that the same muscles are E. (2015), Polypterus and the evolution of fish pectoral Dr. Kathleen Foster [email protected] working harder in walking than during musculature. J. Anat., 226: 511–522. doi:10.1111/joa.12302 Dr. Emily Standen [email protected] swimming (effort and max amplitude). Photo credits: Antoine Morin