Scientists have discovered a way to show the neural activity that indicates the thought processes of a fish while hunting its prey.
"Our work is the first to show brain activities in real time in an intact animal during that animal's natural behavior," said Koichi Kawakami of Japan's National Institute of Genetics in a statement. "We can make the invisible visible; that's what is most important."
The team used a larval zebrafish in their research because during its early stages of development the fish is transparent – they're also cheap and easy to breed. The researchers found the thought processes of the fish could be shown using a very sensitive fluorescent probe, and devised a genetic method for inserting that probe right into the neurons of interest.
The fish was immobilized in a gel platform for the scan and tempted it with some of its natural food, in this case a swimming paramecium the size of a grain of rice. By moving the food the scientists were able to video pulses of thought swimming through the fish's brain in action as the li'l fellow tracked its prey.
"In the future, we can interpret an animal's behavior, including learning and memory, fear, joy, or anger, based on the activity of particular combinations of neurons," Kawakami said. "This has the potential to shorten the long processes for the development of new psychiatric medications." ®
The full research paper has been published in the latest issue of Current Biology.