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Published on: February 1, 2017
Kármán vortex street detection by the lateral line
Boris P Chagnaud1, Horst Bleckmann, Michael H Hofmann
1Institute of Zoology, University of Bonn, Poppelsdorfer Schloss, Bonn, Germany. B.Chagnaud@uni-bonn.de
Summary
Goldfish (Carassius auratus) use their lateral line system to detect water flow. This study shows lateral line nerve fibers respond to Kármán vortex streets, enabling fish to sense hydrodynamic trails.
Area of Science:
- Hydrodynamics
- Neuroethology
- Sensory Biology
Background:
- The lateral line system in fish is crucial for detecting prey, predators, and navigating complex aquatic environments.
- It senses hydrodynamic stimuli, including vortex streets generated by swimming organisms, which may aid in station holding and spatial orientation.
Purpose of the Study:
- To investigate the neural responses of goldfish anterior lateral line nerve fibers to unidirectional water flow and Kármán vortex streets.
- To determine if the lateral line system can detect and encode the frequency of vortex shedding.
Main Methods:
- Electrophysiological recordings were made from anterior lateral line nerve fibers of goldfish (Carassius auratus).
- Fibers were exposed to controlled unidirectional water flow (10 cm s(-1)) and Kármán vortex streets in a flow tank.
- Analysis included discharge rate and spike train frequency spectra.
Main Results:
- Both unidirectional flow and Kármán vortex streets significantly increased the discharge rate of lateral line nerve fibers compared to still water.
- Exposure to Kármán vortex streets resulted in an increased amplitude of spike train frequency spectra at the vortex shedding frequency.
- This effect was most pronounced when the fish intercepted the edge of the vortex street.
Conclusions:
- Goldfish anterior lateral line nerve fibers respond to Kármán vortex streets, indicating a role in detecting hydrodynamic trails.
- The lateral line system can encode vortex shedding frequency, suggesting it is used for spatial orientation and potentially tracking other swimming fish.
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