Why Scientists Are Putting Flies on Little Treadmills

It seems their little brains respond to motion roughly how your brain does.

Researchers at Stanford University are putting flies on a treadmill.

Why are they putting flies on treadmills? To see how their brains respond to motion.

The scientists claim flies and humans perceive movement in very similar ways and believe the insects could shed new light on how the human brain processes information.

As the fly shown in our video goes through its paces at Stanford University, it's being shown moving objects on a tiny panoramic screen. Researchers at the lab are recording its movements to gauge how it perceives motion.

In another lab, a volunteer – human this time - is watching the same images. His brain activity is also being recorded. (The fly didn't volunteer.)

Thomas Clandinin, an associate professor of neurobiology, says that even though human and flies are at opposite ends of the evolutionary scale - when it comes to perceiving motion, the similarities are surprising.

"The basic building blocks for how the circuits in the fly's brain work are really shockingly similar to the brains of humans and the brains of other vertebrae models that people have studied," Clandinin says. "So the basic algorithms that the brain uses to do very fundamental things in vision seem to be very similar."

And Clandinin says that's important because it helps him to search for clues to human brain function on a much smaller scale. A fly's brain is made up of just 100,000 neurons. The human brain has more than 100 billion.

Move your feet

The tricky part was coming up with a method to accurately record the fly's brain activity - that's where the treadmill comes in, Clandinin says.

"What we do is ask them to move their feet. And essentially we put them on a little treadmill and they are going to move the treadmill themselves and by moving the treadmill they tell us what they saw and we can measure the relationship between what they see and what they do by this kind of automatic report," the scientist says.

Why would anybody want to do this, anyway?

"I think all of this is connected to the larger goal of understanding our brains work both in healthy people and people with psychiatric and neurological diseases," Clandinin says. There are a lot of psychiatric and neurological disorders that afflict many of us where our existing treatment strategies are incredibly poor. And in order to make them better there is a broad belief and a strong belief that I hold is that we need to know how the brain works in more detail in order to make a rational design for these kinds of therapeutic strategies."

To do that, Clandinin says he and his team must first try to identify the neural networks flies use to solve problems produced by motion. He says the ability to map the human brain is many years into the future but for now, the humble fly is giving them a running start.

Eliahu Hershkovitz