The sensory superpower that helps fish navigate

18 May 2020



The brain networks that allow fish to detect water flow in their surroundings have been described by Queensland Brain Institute researchers for the first time.

Humans mainly rely on their vision and sound to navigate their surroundings, but fish have a sensory superpower that humans lack: they can sense the flow of water around them, complemented by their vision.

Sensing movements in the water is critical to the behaviour and survival of fish and amphibians—enabling them to swim with the flow, to evade predators, to form schools and capture prey.

Until now, how fish brains interpret water flow has been a mystery.

Using cutting-edge microscopy, Dr Gilles Vanwalleghem and Associate Professor Ethan Scott captured images of larval zebrafish brain activity whilst the fish experienced water flow in their surroundings.  

“We took images of the activity of individual neurons (nerve cells) across the entire brains of larval zebrafish, revealing all the responses and the location of these responses in the brain, during the water flow,” Dr Vanwalleghem said.

“We tested two directions of flow, either head to tail - as if the fish was swimming - or tail to head - as if the fish was being sucked in by a predator, and found that some neurons respond to both directions, others are specific for head-to-tail flow, while other neurons respond to a flow from tail to head.

“By tracking thousands of neurons and their activity through time, we were able to identify the ways in which neurons respond when water flow events happen, and the functional networks they may form across the brain.”

Associate Professor Scott said his research group is interested in the workings of the brain at the level of cells and circuits. 

“Studying navigation in this study, we aim to understand how sensory stimuli are perceived and processed in the brain, and how the brain then interprets these stimuli to produce adaptive behaviours,” Associate Professor Scott said.  

The research was published in The Journal of Neuroscience and supported by organisations including the Australian Research Council, the National Health and Medical Research Council and the European Molecular Biology Organization.