Featured Research

from universities, journals, and other organizations

Neural Noise Created During Binocular Rivalry

Date:
June 21, 2009
Source:
Vanderbilt University
Summary:
Neural "noise" may cause you to miss important changes in your environment when you are concentrating on something else, new research indicates.

Neural "noise" may cause you to miss important changes in your environment when you are concentrating on something else, new research indicates.

The research by Sam Ling, a postdoctoral researcher in Vanderbilt University's Psychology Department, and Randolph Blake, Centennial Professor of Psychology, is currently in press at Psychological Science.

"We found that when the brain actively ignores the presence of an object in the environment, it does so in a way that weakens and degrades residual information about that object," Ling said. "We found that the brain's neural representation of an object outside your window of awareness is not only weaker, but also 'noisier.' It's as if the brain turns down the contrast on your mental television and also adds static noise into the image."

The new research explored what is happening to an ignored stimulus during binocular rivalry, which occurs when the two eyes view radically different images. The brain temporarily rejects, or suppresses, one of those images in favor of the other. The image that commands our visual awareness switches between the two over time. This fluctuation in visual awareness enables cognitive neuroscientists to study the neural correlates of awareness and consciousness.

It has been known for years that the neural representation of a visual stimulus temporarily erased from awareness during binocular rivalry is weaker in strength as a result. Ling and Blake set out to discover if there were other consequences associated with this weakening process.

To do so, the researchers tested people on a simple task that required them to judge the orientation of a pattern, called a grating, composed of parallel contours that tilted either clockwise or counterclockwise. Ordinarily, people are able to distinguish tilts as small as a few degrees. However, when the pattern was presented to an eye that was in this suppressed state, people were significantly worse at the task, sometimes confusing orientations that differed by 10 degrees.

"The problem wasn't that people couldn't see the gratings, because we made them sufficiently high contrast so they could overcome suppression and break into consciousness," Blake said. "Nonetheless, because it was going to a suppressed eye, the grating underwent some sort of general degradation in the fidelity with which it was being registered. Neural noise could explain this."

In an attempt to identify the source of the added noise, Ling and Blake performed a second experiment where observers were asked simply to detect a grating of a given orientation presented within a band of visual noise that the investigators themselves produced on the testing monitor. Ordinarily, observers are able to ignore noise that differs in orientation from a test grating, indicating that the brain cells detecting the grating are responsive to only a limited range of orientations. During suppression, however, the range of interfering orientations was widened considerably, thereby expanding the range of noise orientations that interfered with detection of the test grating.

"We believe this temporary broadening of the 'tuning' of orientation during suppression is a prime candidate as the cause of the reduced fidelity of the neural representation of orientation during suppression," Ling said.

Blake is an investigator in the Vanderbilt Kennedy Center for Research on Human Development. This research was supported with funding from the National Institutes of Health.


Story Source:

The above story is based on materials provided by Vanderbilt University. Note: Materials may be edited for content and length.


Cite This Page:

Vanderbilt University. "Neural Noise Created During Binocular Rivalry." ScienceDaily. ScienceDaily, 21 June 2009. <www.sciencedaily.com/releases/2009/06/090619112337.htm>.
Vanderbilt University. (2009, June 21). Neural Noise Created During Binocular Rivalry. ScienceDaily. Retrieved April 17, 2014 from www.sciencedaily.com/releases/2009/06/090619112337.htm
Vanderbilt University. "Neural Noise Created During Binocular Rivalry." ScienceDaily. www.sciencedaily.com/releases/2009/06/090619112337.htm (accessed April 17, 2014).

Share This



More Mind & Brain News

Thursday, April 17, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Are School Dress Codes Too Strict?

Are School Dress Codes Too Strict?

AP (Apr. 16, 2014) Pushing the limits on style and self-expression is a rite of passage for teens and even younger kids. How far should schools go with their dress codes? The courts have sided with schools in an era when school safety is paramount. (April 16) Video provided by AP
Powered by NewsLook.com
Could Even Casual Marijuana Use Alter Your Brain?

Could Even Casual Marijuana Use Alter Your Brain?

Newsy (Apr. 16, 2014) A new study conducted by researchers at Northwestern and Harvard suggests even casual marijuana use can alter your brain. Video provided by Newsy
Powered by NewsLook.com
Couples Who Sleep Less Than An Inch Apart Might Be Happiest

Couples Who Sleep Less Than An Inch Apart Might Be Happiest

Newsy (Apr. 16, 2014) A new study by British researchers suggests couples' sleeping positions might reflect their happiness. Video provided by Newsy
Powered by NewsLook.com
Cognitive Function: Is It All Downhill From Age 24?

Cognitive Function: Is It All Downhill From Age 24?

Newsy (Apr. 15, 2014) A new study out of Canada says cognitive motor performance begins deteriorating around age 24. Video provided by Newsy
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:
from the past week

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