Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

New slant on vision research: Neurons sensitive to viewing angle

03.03.2005


Mistakes made by human subjects in identifying the facing direction of faces, cars or meaningless objects have yielded evidence that the brain contains nerve cells, or neurons, whose job is to encode the viewing angle of objects. It is well known that certain neurons respond to color, motion, edges and other aspects of our environment. Now, University of Minnesota researchers have found that our visual cortex contains neurons that tell us, for example, whether a face is turned in our direction or not. The work adds to knowledge of how the brain collects and processes visual information leading to the recognition of objects, and it may inform the design of machine vision. The study will be published in the March 3 issue of the journal Neuron.

The brain relies on millions of neurons to report the visual elements of our environment. But, for example, if every neuron geared to motion fired in response to any motion whatsoever, then we couldn’t tell whether a train was chugging into the distance or bearing down on us. Instead, to gain a complete picture of the world, our brains appear to contain separate, but physically intertwined, populations of neurons that respond to only one small aspect of our environment. The brain then bases its interpretation of images largely on which neurons fire.

"The issue is, what is the underlying neural mechanism that supports the ability to recognize objects viewed from different angles?" said Sheng He, associate professor of psychology, who directed the study. "This study supports the idea that we have explicit representations in our brains for specific views of objects." The study was carried out jointly with Fang Fang, a graduate student in He’s laboratory.



The researchers presented volunteers with the image of a face, a car or a meaningless geometric object on the computer. In each case, the first image--called the adapting image--was turned to one side. After a very brief pause, another image of the same face or object--called the test image--was flashed on the screen. But this time, the image was either head-on or turned very slightly (three or six degrees) to one side or the other. Whatever the orientation of the test image, subjects were required to choose whether it was turned to the right or the left.

When subjects were presented with an adapting image turned 30 degrees to one side, then tested with an image of the same thing in head-on view, they tended to say the test image was tilted in the opposite direction of the adapting image. That is, if they first saw the face of a man turned 30 degrees to the left, then saw his face head-on, they said the face was turned to the right. This "adaptation effect" occurred 80 percent of the time; normally, responses for both directions would be equally likely. Even if the test image was turned three degrees in the same direction as the adapting image, the subjects guessed wrong half the time, saying the test image was turned in the other direction.

The reason for the errors is that when a person stares at an image, neurons that respond to the viewing angle of the image get "tired" and become less responsive when a very similar image is presented again, He said. The brain interprets this lack of response as the object not being turned in the direction the neurons are attuned to. This suggests that there are separate populations of neurons, each responding to a particular narrow range of orientations. The neurons are likely located in the lateral occipital cortex, an area of the cerebral cortex very far back on either side of the head.

The researchers also performed experiments that suggested that for faces, at least, subjects were not deciding the orientation of test images based on "local" features such as noses. When subjects saw unorganized fragments of faces--as if parts of the face were simply erased--as adapting images, no adaptation effect occurred.

"This shows that fragmented local features are not sufficient to get the adaptation effect," He said. "You must have a global representation of the face. But local features may be important within the context of a [complete] face.

"Also, if you adapt to a face, then test with an image of a car, you don’t get adaptation. So local features that identify the object as a face or a car are important. Researchers think there are populations of neurons that respond to classes of objects in the environment, for example, houses, hills, tools, faces and so forth."

The researchers next plan to put volunteers in a functional magnetic resonance imaging scanner and see how different neurons respond to different views of objects. The work was supported by the James S. McDonnell Foundation, the National Institutes of Health and the University of Minnesota.

Sheng He | EurekAlert!
Further information:
http://www1.umn.edu/twincities/index.php

More articles from Studies and Analyses:

nachricht New study: How does Europe become a leading player for software and IT services?
03.04.2017 | Fraunhofer-Institut für System- und Innovationsforschung (ISI)

nachricht Reusable carbon nanotubes could be the water filter of the future, says RIT study
30.03.2017 | Rochester Institute of Technology

All articles from Studies and Analyses >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Making lightweight construction suitable for series production

More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.

Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...

Im Focus: Wonder material? Novel nanotube structure strengthens thin films for flexible electronics

Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.

"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...

Im Focus: Deep inside Galaxy M87

The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.

Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...

Im Focus: A Quantum Low Pass for Photons

Physicists in Garching observe novel quantum effect that limits the number of emitted photons.

The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...

Im Focus: Microprocessors based on a layer of just three atoms

Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.

Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Fighting drug resistant tuberculosis – InfectoGnostics meets MYCO-NET² partners in Peru

28.04.2017 | Event News

Expert meeting “Health Business Connect” will connect international medical technology companies

20.04.2017 | Event News

Wenn der Computer das Gehirn austrickst

18.04.2017 | Event News

 
Latest News

Wireless power can drive tiny electronic devices in the GI tract

28.04.2017 | Medical Engineering

Ice cave in Transylvania yields window into region's past

28.04.2017 | Earth Sciences

Nose2Brain – Better Therapy for Multiple Sclerosis

28.04.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>