Featured Research

from universities, journals, and other organizations

Rats have a double view of the world

Date:
May 27, 2013
Source:
Max-Planck-Gesellschaft
Summary:
Scientists using miniaturized high-speed cameras and high-speed behavioral tracking have discovered that rats move their eyes in opposite directions in both the horizontal and the vertical plane when running around. Each eye moves in a different direction, depending on the change in the animal's head position. An analysis of both eyes' field of view found that the eye movements exclude the possibility that rats fuse the visual information into a single image like humans do. Instead, the eyes move in such a way that enables the space above them to be permanently in view -- presumably an adaptation to help them deal with the major threat from predatory birds that rodents face in their natural environment.

Rats process visual information from their eyes similar to other mammals. Nevertheless, their eyes move in a very different way. Unlike humans, their eyes can move in opposite directions.
Credit: © MPI for Biological Cybernetics/Kerr

Scientists from the Max Planck Institute for Biological Cybernetics in Tόbingen, using miniaturised high-speed cameras and high-speed behavioural tracking, discovered that rats move their eyes in opposite directions in both the horizontal and the vertical plane when running around. Each eye moves in a different direction, depending on the change in the animal's head position. An analysis of both eyes' field of view found that the eye movements exclude the possibility that rats fuse the visual information into a single image like humans do. Instead, the eyes move in such a way that enables the space above them to be permanently in view -- presumably an adaptation to help them deal with the major threat from predatory birds that rodents face in their natural environment.

Related Articles


Like many mammals, rats have their eyes on the sides of their heads. This gives them a very wide visual field, useful for detection of predators. However, three-dimensional vision requires overlap of the visual fields of the two eyes. Thus, the visual system of these animals needs to meet two conflicting demands at the same time; on the one hand, maximum surveillance and on the other hand, detailed binocular vision.

The research team from the Max Planck Institute for Biological Cybernetics have now, for the first time, observed and characterised the eye movements of freely moving rats. They fitted minuscule cameras weighing only about one gram to the animals' heads, which could record the lightning-fast eye movements with great precision. The scientists also used another new method to measure the position and direction of the head, enabling them to reconstruct the rats' exact line of view at any given time.

The Max Planck scientists' findings came as a complete surprise. Although rats process visual information from their eyes through very similar brain pathways to other mammals, their eyes evidently move in a totally different way. "Humans move their eyes in a very stereotypical way for both counteracting head movements and searching around. Both our eyes move together and always follow the same object. In rats, on the other hand, the eyes generally move in opposite directions," explains Jason Kerr from the Max Planck Institute for Biological Cybernetics.

In a series of behavioural experiments, the neurobiologists also discovered that the eye movements largely depend on the position of the animal's head. "When the head points downward, the eyes move back, away from the tip of the nose. When the rat lifts its head, the eyes look forward: cross-eyed, so to speak. If the animal puts its head on one side, the eye on the lower side moves up and the other eye moves down." says Jason Kerr.

In humans, the direction in which the eyes look must be precisely aligned, otherwise an object cannot be fixated. A deviation measuring less than a single degree of the field of view is enough to cause double vision. In rats, the opposing eye movements between left and right eye mean that the line of vision varies by as much as 40 degrees in the horizontal plane and up to 60 degrees in the vertical plane. The consequence of these unusual eye movements is that irrespective of vigorous head movements in all planes, the eyes movements always move in such a way to ensure that the area above the animal is always in view simultaneously by both eyes -- something that does not occur in any other region of the rat's visual field.

These unusual eye movements that rats possess appear to be the visual system's way of adapting to the animals' living conditions, given that they are preyed upon by numerous species of birds. Although the observed eye movements prevent the fusion of the two visual fields, the scientists postulate that permanent visibility in the direction of potential airborne attackers dramatically increases the animals' chances of survival.


Story Source:

The above story is based on materials provided by Max-Planck-Gesellschaft. Note: Materials may be edited for content and length.


Journal Reference:

  1. Damian J. Wallace, David S. Greenberg, Juergen Sawinski, Stefanie Rulla, Giuseppe Notaro, Jason N. D. Kerr. Rats maintain an overhead binocular field at the expense of constant fusion. Nature, 2013; DOI: 10.1038/nature12153

Cite This Page:

Max-Planck-Gesellschaft. "Rats have a double view of the world." ScienceDaily. ScienceDaily, 27 May 2013. <www.sciencedaily.com/releases/2013/05/130527100530.htm>.
Max-Planck-Gesellschaft. (2013, May 27). Rats have a double view of the world. ScienceDaily. Retrieved November 29, 2014 from www.sciencedaily.com/releases/2013/05/130527100530.htm
Max-Planck-Gesellschaft. "Rats have a double view of the world." ScienceDaily. www.sciencedaily.com/releases/2013/05/130527100530.htm (accessed November 29, 2014).

Share This


More From ScienceDaily



More Plants & Animals News

Saturday, November 29, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Research on Bats Could Help Develop Drugs Against Ebola

Research on Bats Could Help Develop Drugs Against Ebola

AFP (Nov. 28, 2014) — In Africa's only biosafety level 4 laboratory, scientists have been carrying out experiments on bats to understand how virus like Ebola are being transmitted, and how some of them resist to it. Duration: 01:18 Video provided by AFP
Powered by NewsLook.com
New Dinosaur Species Found in Museum Collection

New Dinosaur Species Found in Museum Collection

Reuters - Innovations Video Online (Nov. 27, 2014) — A British palaeontologist has discovered a new species of dinosaur while studying fossils in a Canadian museum. Pentaceratops aquilonius was related to Triceratops and lived at the end of the Cretaceous Period, around 75 million years ago. Jim Drury has more. Video provided by Reuters
Powered by NewsLook.com
Tryptophan Isn't Making You Sleepy On Thanksgiving

Tryptophan Isn't Making You Sleepy On Thanksgiving

Newsy (Nov. 27, 2014) — Tryptophan, a chemical found naturally in turkey meat, gets blamed for sleepiness after Thanksgiving meals. But science points to other culprits. Video provided by Newsy
Powered by NewsLook.com
Classic Hollywood Memorabilia Goes Under the Hammer

Classic Hollywood Memorabilia Goes Under the Hammer

Reuters - Entertainment Video Online (Nov. 26, 2014) — The iconic piano from "Casablanca" and the Cowardly Lion suit from "The Wizard of Oz" fetch millions at auction. Sara Hemrajani reports. Video provided by Reuters
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:

Strange & Offbeat Stories

 

Plants & Animals

Earth & Climate

Fossils & Ruins

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins