Neuroscientists look deeper at how fish navigate their environment by wiring their brains to a neuronal activity monitor.
If you have ever wondered how fish get around without bumping into anything underwater, a research team in Israel decided the best way to get the answer was by wiring goldfish brains to a computer.
In a study (via The New York Times) conducted at Ben-Gurion University, researchers outfitted 15 goldfish with a special cyberpunk-esque headgear “to study this fundamental cognitive component in fish” by recording the “activity of neurons in the central area of the goldfish telencephalon while the fish were freely navigating in a quasi-2D water tank embedded in a 3D environment.”
“Navigation is an extremely important aspect of behavior because we navigate to find food, to find shelter, to escape predators,” said Ronen Segev, a neuroscientist at Ben-Gurion University, who was part of the team of team that performed the fish brain surgery.
The surgery involved exposing the brain and attaching electrodes that were the size of a strand of human hair to a recording device that monitored the fish’s brain activity. The surgeries had to be performed out of the water, so the brain surgeons pumped water and anesthetics into the fish’s mouths, ensuring they would survive the procedure.
The monitors, which look like silly little sci-fi hats, were sealed in a waterproof case with a bit of plastic foam at the top to keep it buoyant enough so the fish could swim normally and not be weighed down.
Once the goldfish recovered from their surgeries, they participated in swimming trials that involved navigating a special tank two feet long and six inches wide. What researchers discovered was that as the fish swam closer to the tank’s edge, the navigational cells in their brains fired up.
Another member of the team, Dr. Lear Cohen, says it is easier for a fish “to know the distance from a salient feature in the environment than knowing an exact position.” On the other hand, mammals have special neurons in their brain that essentially try to tell them exactly where they are as their brain draws a mental map of the environment. We see ourselves in specific locations, basically, whereas for fish, it’s more of a relative thing.
That does not look comfortable. (Image credit: Lear Cohen)
This is how fish can navigate the deep dark depths of underwater living and get around constantly shifting currents and low visibility that would otherwise disorient a mammal. Dr. Cohen suspects that other animals have various navigation circuits in their brains designed to accommodate their particular habitats.
Dr. Adelaide Sibeaux, a biologist at Oxford, told the Times that these experiments are important because “We’re modifying a lot of animals’ environments, and, if you understand how an animal navigates, you will know if they are able to cope with changes that are happening in the world at the moment.”
And if you are wondering how the fish are doing after receiving their cybernetic upgrades? Well, not great. Researchers euthanized the fish once they completed their swimming trials so they could further examine their brains. The experiment was approved by Oxford’s animal welfare committee.
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