Flies, humans perceive motion in same way, study finds

January 24, 2014 by Becky Bach
Close-up of the head of Calliphora vomitoria. Credit: Wikipedia.

(Medical Xpress)—Anyone who has tried to swat a fly knows they can quickly spot – and evade – the approaching swatter. New research from a team of Stanford scientists might explain why: Flies and humans share a computational strategy to perceive motion.

"What's really exciting to me is that no one would have expected this deep similarity between two animals that are so evolutionarily different," said Stanford's Thomas Clandinin, an associate professor of neurobiology and one of the authors of the study, which was published this month in the journal Nature Neuroscience.

The last common ancestor of flies and humans lived more than 500 million years ago when the planet looked quite different. Nonetheless, repeated patterns in the natural environment led ancestors of both organisms to evolve similar strategies to sense movement.

It is likely this model evolved twice – once in a ancestor and once for a fly ancestor – because flies and humans are so far apart on the evolutionary tree, according to neurobiologist Damon Clark, a lead author of the paper. Despite the fact that the brains of humans and flies are quite different, they analyze in similar ways. Clark, now a professor at Yale, was a Stanford postdoctoral researcher in Clandinin's group at Stanford when he worked on the project.

Scientists know quite a bit about how the eye detects light. However, they don't completely understand how the brain translates a series of chemical signals into an image. The research team examined motion perception in flies and humans to learn more about the visual system and the brain's problem-solving strategies.

The video will load shortly

"The big question is really 'How does the brain evolve,'" said Anthony Norcia, an author of the paper and a Stanford professor (research) of psychology.

The study suggests there may be an optimal way to view natural moving objects which share fundamental properties, Clark said. By statistically modeling these properties, theoretical neuroscientist James Fitzgerald, also a lead author of the paper, was able to develop a framework to test these theories, team members said. Fitzgerald was previously a graduate student at Stanford and is now a postdoctoral fellow at Harvard University.

Both humans and flies discern three types of information about a moving object: its speed, direction of motion and brightness. Previous models were flawed because they discarded information about brightness, Norcia said.

The team tested its theories in both humans and flies. In Norcia's lab, volunteers watched videos while researchers monitored their scalp electroencephalogram (EEG) signals. They also answered questions about their perception of motion based on the videos.

But to test flies, researchers couldn't just ask them which way an image was moving. Instead, Clark said, they capitalized on a known fly trait: Flies turn in the direction of motion. Clark tethered flies to sticks, posed them on tiny spherical treadmills, and then screened videos while monitoring their movements.

The project was possible thanks to the kind of interdisciplinary teamwork that is common at Stanford, Norcia said. It started when Clark gave an informal presentation in the Department of Psychology, piquing the interest of Norcia and the study's third lead author, former Stanford postdoctoral researcher Justin Ales, who is now a lecturer at the University of St. Andrews in Scotland.

Fitzgerald said he chose to study motion in flies because it could be possible to pinpoint the neural networks involved. "The ultimate hope is by finding an example of how solve this particular problem, it could give us some insight into how the brain solves problems more generally," Fitzgerald said.

Explore further: An optical illusion called 'reverse-phi motion' helps explain how we view moving objects

More information: "Flies and humans share a motion estimation strategy that exploits natural scene statistics." Damon A Clark, James E Fitzgerald, Justin M Ales, Daryl M Gohl, Marion A Silies, Anthony M Norcia, Thomas R Clandinin. Nature Neuroscience (2014) DOI: 10.1038/nn.3600. Received 12 August 2013 Accepted 14 November 2013 Published online 05 January 2014

Related Stories

An optical illusion called 'reverse-phi motion' helps explain how we view moving objects

September 12, 2011
(PhysOrg.com) -- Flies like watching computer screens as much as the next animal. Set them on a trackball in front of a monitor, and they'll follow the action – if the images in front of them move in one direction, the ...

Tracking down motion perception

June 22, 2011
Neurobiologists have determined the number of circuits needed to see movements.

Study unlocks secret of how fruit flies choose fruit with just the right amount of ethanol

December 10, 2013
(Phys.org) —Researchers from the University of California working with a team at Howard Hughes Medical Institute in Virginia, have discovered how it is that fruit flies are able to lay their eggs in rotting fruit that has ...

Neurobiologists discover elementary motion detectors in the fruit fly

August 7, 2013
Recognising movement and its direction is one of the first and most important processing steps in any visual system. By this way, nearby predators or prey can be detected and even one's own movements are controlled. More ...

From bacteria to lions – how tiny proteins which control our responses to both could be linked

July 29, 2013
New research from the University of Birmingham and the University of Cambridge has uncovered a relationship between proteins that control immunity and proteins that control activity in the brain.

Recommended for you

'Residual echo' of ancient humans in scans may hold clues to mental disorders

July 26, 2017
Researchers at the National Institute of Mental Health (NIMH) have produced the first direct evidence that parts of our brains implicated in mental disorders may be shaped by a "residual echo" from our ancient past. The more ...

Cellular roots of anxiety identified

July 26, 2017
From students stressing over exams to workers facing possible layoffs, worrying about the future is a normal and universal experience. But when people's anticipation of bad things to come starts interfering with daily life, ...

Laser used to reawaken lost memories in mice with Alzheimer's disease

July 26, 2017
(Medical Xpress)—A team of researchers at Columbia University has found that applying a laser to the part of a mouse brain used for memory storage caused the mice to recall memories lost due to a mouse version of Alzheimer's ...

Brain disease seen in most football players in large report

July 25, 2017
Research on 202 former football players found evidence of a brain disease linked to repeated head blows in nearly all of them, from athletes in the National Football League, college and even high school.

Zebrafish study reveals clues to healing spinal cord injuries

July 25, 2017
Fresh insights into how zebrafish repair their nerve connections could hold clues to new therapies for people with spinal cord injuries.

Lutein may counter cognitive aging, study finds

July 25, 2017
Spinach and kale are favorites of those looking to stay physically fit, but they also could keep consumers cognitively fit, according to a new study from University of Illinois researchers.

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.