Evolutionary convergence of a neural mechanism in the cavefish lateral line system
- University of Florida, United States
- Florida Atlantic University, United States
- Texas A&M University, United States
Abstract
Animals can evolve dramatic sensory functions in response to environmental constraints, but little is known about the neural mechanisms underlying these changes. The Mexican tetra, Astyanax mexicanus, is a leading model to study genetic, behavioral, and physiological evolution by comparing eyed surface populations and blind cave populations. We compared neurophysiological responses of posterior lateral line afferent neurons and motor neurons across A. mexicanus populations to reveal how shifts in sensory function may shape behavioral diversity. These studies indicate differences in intrinsic afferent signaling and gain control across populations. Elevated endogenous afferent activity identified a lower response threshold in the lateral line of blind cavefish relative to surface fish leading to increased evoked potentials during hair cell deflection in cavefish.. We next measured the effect of inhibitory corollary discharges from hindbrain efferent neurons onto afferents during locomotion. We discovered that three independently-derived cavefish populations have evolved persistent afferent activity during locomotion, suggesting for the first time that partial loss of function in the efferent system can be an evolutionary mechanism for neural adaptation of a vertebrate sensory system.
Data availability
Electrophysiology data generated and analysed during this study are included as a supplementary file ('Supplementary File 1').
Article and author information
Author details
Funding
US-Israel Binational Science Foundation (SP#2018-190)
- Alex C Keene
National Science Foundation (IOS165674)
- Alex C Keene
National Institutes of Health (IR01GM127872)
- Alex C Keene
National Institutes of Health (DC010809)
- James C Liao
National Science Foundation (IOS1856237)
- James C Liao
National Science Foundation (IOS2102891)
- James C Liao
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Ethics
Animal experimentation: All animals were handled according to protocols approved by the University of Florida or Florida Atlantic University Institutional Animal Care and Use Committee (IACUC201603267, IACUC202200000056). Animal health was assessed by monitoring blood flow throughout each experiment.
Copyright
© 2022, Lunsford et al.
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.
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Evolutionary convergence of a neural mechanism in the cavefish lateral line system
eLife 11:e77387.
https://doi.org/10.7554/eLife.77387
