Researchers find high-resolution retina cells in mice only activate when birds fly over

Aug 14, 2012 by Bob Yirka report

(Phys.org) -- In the eye, the retina is the light sensitive tissue that lines its inner surface; packed with ganglion neurons, its job is to convert incoming information to something that the brain can understand. In some animals, such as people, cats and the macaque, the density of neurons in certain areas of the retina accounts for the highest resolution images sent to the brain. But some animals apparently reserve such areas for other jobs. Mice for example, according to new research by a team from Harvard, only use their high resolution areas when under threat from above. As they describe in their paper published in the Proceedings of the National Academy of Sciences, the team notes that high density neural areas in the retinas of mice are only activated when shadows from birds flying overhead are detected.

In people, the highly dense parts of the retina are used virtually every waking moment. When focusing on something, the of is busy converting light to images that are sent to the brain via the . The only time this process quiets is when people are either lost in thought, or asleep. With mice, according to this new research, things are very different.

To find out how mice use their high-resolution ganglion, the team attached a to a rat volunteer and then watched to see what sorts of things it focused on. Next, they played the video back directly onto the retinas of several test mice while simultaneously monitoring neural cell activity. In so doing, they found that the high-resolution cells sat mostly quiet, doing nothing.

As it turned out, the cells weren’t actually doing nothing, they were waiting.

When silhouettes of birds were projected overhead, the waiting ended as the ganglia sprang into action, interpreting every movement. This shows, the researchers say, that the high-resolution neuron groups in mice retinas serve not as interpreters of everyday life, but as highly specific predator detectors. More specifically they found the nerves reacted when the birds were in their center of view, meaning close and ready to snatch them up. Sadly, they also found that the nerves quit firing once the birds came close enough, indicating the mice were doomed.

After testing several scenarios, the team found that the retina cells in the mice tended to fire when detecting virtually any object that appeared against a blank backdrop, which was also moving, such as is the case of a bird flying in the sky. Thus it appears, for mice, it’s better to focus sharply only when predators from the sky are near, so as to best prepare for a quick emergency plan.

Explore further: The malaria pathogen's cellular skeleton under a super-microscope

More information: PNAS August 13, 2012 doi: 10.1073/pnas.1211547109

Related Stories

Immune cells help heal eye injury in mice

Jan 10, 2011

A paper published online on January 10 in the Journal of Experimental Medicine reports that retinal ganglion cells—neurons in the eye—are rescued by immune cells that infiltrate the mouse retina after eye injury ...

New Growth in Old Eyes

Aug 24, 2006

Nerve cells in the retinas of elderly mice show an unexpected and purposeful burst of growth late in life, according to researchers at UC Davis.

Algae may be the solution to blindness

Apr 15, 2011

(PhysOrg.com) -- The song about three blind mice may just be a song of the past according to new research presented by neuroscientist Alan Horsager from the Institute of Genetic Medicine at the University of Southern California ...

Recommended for you

For resetting circadian rhythms, neural cooperation is key

8 hours ago

Fruit flies are pretty predictable when it comes to scheduling their days, with peaks of activity at dawn and dusk and rest times in between. Now, researchers reporting in the Cell Press journal Cell Reports on April 17th h ...

Rapid and accurate mRNA detection in plant tissues

10 hours ago

Gene expression is the process whereby the genetic information of DNA is used to manufacture functional products, such as proteins, which have numerous different functions in living organisms. Messenger RNA (mRNA) serves ...

For cells, internal stress leads to unique shapes

Apr 16, 2014

From far away, the top of a leaf looks like one seamless surface; however, up close, that smooth exterior is actually made up of a patchwork of cells in a variety of shapes and sizes. Interested in how these ...

User comments : 0

More news stories

Deadly human pathogen Cryptococcus fully sequenced

Within each strand of DNA lies the blueprint for building an organism, along with the keys to its evolution and survival. These genetic instructions can give valuable insight into why pathogens like Cryptococcus ne ...

Better thermal-imaging lens from waste sulfur

Sulfur left over from refining fossil fuels can be transformed into cheap, lightweight, plastic lenses for infrared devices, including night-vision goggles, a University of Arizona-led international team ...

Hackathon team's GoogolPlex gives Siri extra powers

(Phys.org) —Four freshmen at the University of Pennsylvania have taken Apple's personal assistant Siri to behave as a graduate-level executive assistant which, when asked, is capable of adjusting the temperature ...