Scientists have created the first ever video of neurons firing in a freely moving animal, a technique that could lead to greater understanding about how our own brains work. The Princeton-led team first programmed a nematode worm's neurons to create a fluorescent protein that lit up in response to calcium. Since calcium is generally present when a neuron fires, that means they could literally visualize the 1 millimeter-long worm "thinking" as it wriggles around. The resulting video (below) shows 77 of the nematode's 302 neurons working in the top panel, while the bottom panel simultaneously shows its activities and brain position.
According to their paper, the researchers used a special microscope and software -- similar to that used in games and self-driving cars -- that tracked the animal's head in real time. Multiple cameras then recorded the animal in close-up and wide views while a motorized platform kept it in the field of view. The resulting video is a fascinating look at how neurons work together during simple activities. While the team chose the nematode because of the animal's simple brain structure, they were surprised at the number of neurons the worm used just to turn around.
Research author Andrew Leifer told News at Princeton that the work represents a new step in studying and recording animals' brains under more natural conditions. However, he admits that "the technology needed to perform similar recordings in humans is many years away." Nevertheless, the team plans to use the data to construct a computer model of brain function by comparing neural activity to real-life behavior. "By studying how the brain works in a simple animal like the worm ... we hope to gain insights into how collections of neurons work that are universal for all brains, even humans," he said. They may also want to give the OpenWorm Project folks a call.