Goldfish Turned Into a Cyborg: Scientists Attempt To Record Neuronal Activity of the Fish To Understand Their Evolution

Scientists have implanted electrodes into the skulls of goldfish to record their neural activity. The fish looks like a cyberfish with headgear, which would study brain mechanisms of fish navigation as well as their link to the evolutionary origins of navigation in all animals.

In the study, titled "Boundary Vector Cells in the Goldfish Central Telencephalon Encode Spatial Information" published in PLOS One, researchers fitted 15 goldfish with cybernetic headgear.

Putting on a Headgear to a Goldfish

Ronen Segev, a neuroscientist at the Ben-Gurion University of the Negev in Israel, stated that navigation is an important aspect of behavior since animals need it to find food, shelter, and escape predators.

According to the New York Times, the team implanted electrodes into the skull of the goldfish to study how neurons fire in its brain. However, it was not an easy task.

To successfully implant a computer inside the brain of the fish, it would take some careful hands because the brain is so small that it looks like a cluster of lentils, which is only 0.5 inches long.

Neuroscientist Lear Cohen, a doctoral candidate at Ben-Gurion who also performed brain surgeries to implant the devices, said that they exposed the brain and put the electrodes inside with the aid of a microscope. He noted that every electrode they implanted is about the diameter of a strand of hair.

Moreover, what makes it trickier to implant is finding a way to perform the procedure on dry land without harming the goldfish. Cohen noted that fish needs water; but at the same time, they should not be moving during the procedure. So, he and his colleagues pumped water and anesthetics into the mouth of the goldfish.

After successfully implanting the electrodes, they connected them to a small recording device that monitors neuronal activity. This device was sealed in a waterproof case and placed on top of the fish's forehead. They then attached the buoyant plastic foam to the device to avoid the computer from weighing the fish down and obstructing its ability to swim.

Goldfish Navigation System Different From Mammals

The goldfish in the experiment seem to be wearing a headgear after recovering from surgery, as per a similar report from The Seattle Times. The fish swam in a 2-foot-long, 6-inch-wide tank, and their navigational cells lit up the closer they swam to the tank's edges.

The findings revealed that goldfish use a different type of neuron system than mammals, which specialize in pinpointing their exact location within their surroundings. The study revealed that goldfish rely on neurons that signal the fish when an obstacle or boundary is approached. By combining various barrier distances, the fish can orient themselves in space.

Unlike mammals that use cells to determine "I'm here, I'm here, I'm here," the goldfish relied on neurons that delivered a different message. Instead, they informed the fish of their position along one axis and another axis.

Overall, the study suggested that different animals use various navigation circuits to correspond with the challenges they face moving around their environments. For instance, the ever-shifting currents of a watery home could mean that, for fish, it's easier to gauge the distance from a salient feature in their surroundings than know an exact location.

Check out more news and information on Animals in Science Times.