Like humans, cockroaches use GPS to move around

New York, July 10

Rats, humans and cockroaches have a system similar to the Global Positioning System (GPS) in their heads that allows them to navigate new surroundings, researchers have discovered.

A team of researchers from Case Western Reserve University in the US recorded the activity in the brain of a restrained cockroach and found that insects use sight and a vestibular-like system to track direction and angle.

The finding, published in journal Current Biology, is an example of convergent evolution -- distinct animals developed similar systems to manage the same problems.

"We've known that a mammal can come into a new area and, after a short period of being disoriented, find its way around," said Roy Ritzmann, a Biology Professor at Case Western Reserve and an author of the new study.

Humans and other mammals rely on head-direction, place and grid cells in their brains to process, integrate and update sensory information. The cues come from the direction they look, what they see and motion, he said.

"Orienting contributes to spatial memory, so they can return to point A or navigate to something they like or away from something they don't like," said PhD student Adrienn G. Varga, lead author of the study.

By repeating experiments that uncovered head-direction cells in rats, Ritzmann and Varga found head-direction-like activity and evidence of contextual cue processing in cockroaches.

When the researchers closely examined the activity of central complex cells, they found that some neurons appear to encode head direction like a compass, while others appeared to encode the relative direction of the rotation after each stop, storing navigational context.

"The fact we found these cell activities that are very similar to those in mice and rats and us strongly indicates insects rely on the same sensory inputs we need to orient ourselves and their brains process these inputs in a similar manner," Varga said.

Ritzmann said either humans and cockroaches have a common ancestor and this capability was retained or, more likely, represents convergent evolution. — IANS