Featured Research

from universities, journals, and other organizations

People blind from birth use visual brain area to improve other senses: Can hear and feel with greater acuity

Date:
October 10, 2010
Source:
Georgetown University Medical Center
Summary:
People who have been blind from birth make use of the visual parts of their brain to refine their sensation of sound and touch, according to an international team of researchers.

A blind woman navigates through construction on a sidewalk
Credit: iStockphoto/Karin Lau

People who have been blind from birth make use of the visual parts of their brain to refine their sensation of sound and touch, according to an international team of researchers led by neuroscientists at Georgetown University Medical Center (GUMC).

Published in the journal Neuron, the scientists say this finding helps explain why the blind have such advanced perception of these senses -- abilities that far exceed people who can see, they say.

Using functional magnetic resonance imaging (fMRI), the researchers found that the blind use specialized "modules" in the visual cortex that process the spatial location of an object when a person localizes it in space. More generally, they believe that the different functional attributes that make up vision, such as analysis of space, patterns, and motion, still exist in the visual cortex of blind individuals. But instead of using those areas to understand what the eyes see, the blind use them to process what they hear and touch because the same components are necessary to process information from those senses.

"We can see that in the blind, large parts of the visual cortex light up when participants are engaged in auditory and tactile tasks. This is in addition to the areas in their brain that are dedicated to processing sound and touch," says the study's lead investigator, Josef P. Rauschecker, PhD, professor in the Department of Physiology and Biophysics at GUMC.

"This shows us that the visual system in the blind retains the functional organization that was anatomically laid out by genetics, but that the brain is plastic enough to use these modules to analyze input they receive from different senses,' he says.

In this experiment, which included researchers from Belgium and Finland, 12 sighted and 12 blind participants agreed to perform a set of auditory or tactile tasks. "We know that in the blind, the brain reroutes other sensory inputs to unused portions of the brain to compensate for loss of sight, but we wondered what specifically the visual cortex in these individuals was doing," Rauschecker says. "The visual cortex is one of the largest and most powerful parts of the brain, with about 40 different specialized modules. By comparison, the auditory processing center in the brain only has about 20 modules."

In one task, volunteers wore stereo headphones while in the fMRI machine, and they reported where in space the variety of sounds they heard came from. In the other test, they wore piezo-electric vibrators on each finger, and the goal was to report which finger was being gently stimulated.

"We found that the visual cortex in the blind was much more strongly activated than it was in the sighted, where visual cortex was mostly deactivated by sounds and touch," Rauschecker says. "Furthermore, there was a direct correlation between brain activity and performance in the blind. The more accurate blind people were in solving the spatial tasks, the stronger the spatial module in the visual cortex was activated.

"That tells us that the visual cortex in the blind takes on these functions and processes sound and tactile information which it doesn't do in the sighted," he says. "The neural cells and fibers are still there and still functioning, processing spatial attributes of stimuli, driven not by sight but by hearing and touch. This plasticity offers a huge resource for the blind."

Clinically, the results suggest that these powerful senses may potentially be harnessed to help the blind better navigate in their world, Rauschecker says. For example, GUMC researchers, collaborating with colleagues in Belgium, are developing goggles that process visual stimuli and turn them into auditory cues that help guide the blind. This sensory substitution device is now being tested in volunteers.

Co-authors of the study include Laurent A. Renier, PhD and Anne G. DeVolder, PhD from the Université Catholique de Louvain, in Brussels; Irina Anurova, PhD and Synnöve Carlson, PhD from Aalto University School of Science and Technology in Helsinki; and John VanMeter, PhD, from GUMC.

This work was funded by the National Eye Institute, the National Institute for Neurological Disorders and Stroke, the National Science Foundation, the Academy of Finland, and the Belgian American Educational Foundation.


Story Source:

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


Journal Reference:

  1. Laurent A. Renier, Irina Anurova, Anne G. De Volder, Synnöve Carlson, John VanMeter, Josef P. Rauschecker. Preserved Functional Specialization for Spatial Processing in the Middle Occipital Gyrus of the Early Blind. Neuron, 2010; 68 (1): 138-148 DOI: 10.1016/j.neuron.2010.09.021

Cite This Page:

Georgetown University Medical Center. "People blind from birth use visual brain area to improve other senses: Can hear and feel with greater acuity." ScienceDaily. ScienceDaily, 10 October 2010. <www.sciencedaily.com/releases/2010/10/101006131203.htm>.
Georgetown University Medical Center. (2010, October 10). People blind from birth use visual brain area to improve other senses: Can hear and feel with greater acuity. ScienceDaily. Retrieved July 31, 2014 from www.sciencedaily.com/releases/2010/10/101006131203.htm
Georgetown University Medical Center. "People blind from birth use visual brain area to improve other senses: Can hear and feel with greater acuity." ScienceDaily. www.sciencedaily.com/releases/2010/10/101006131203.htm (accessed July 31, 2014).

Share This




More Health & Medicine News

Thursday, July 31, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Health Insurers' Profits Slide

Health Insurers' Profits Slide

Reuters - Business Video Online (July 30, 2014) — Obamacare-related costs were said to be behind the profit plunge at Wellpoint and Humana, but Wellpoint sees the new exchanges boosting its earnings for the full year. Fred Katayama reports. Video provided by Reuters
Powered by NewsLook.com
Concern Grows Over Worsening Ebola Crisis

Concern Grows Over Worsening Ebola Crisis

AFP (July 30, 2014) — Pan-African airline ASKY has suspended all flights to and from the capitals of Liberia and Sierra Leone amid the worsening Ebola health crisis, which has so far caused 672 deaths in Guinea, Liberia and Sierra Leone. Duration: 00:43 Video provided by AFP
Powered by NewsLook.com
At Least 20 Chikungunya Cases in New Jersey

At Least 20 Chikungunya Cases in New Jersey

AP (July 30, 2014) — At least 20 New Jersey residents have tested positive for chikungunya, a mosquito-borne virus that has spread through the Caribbean. (July 30) Video provided by AP
Powered by NewsLook.com
Xtreme Eating: Your Daily Caloric Intake All On One Plate

Xtreme Eating: Your Daily Caloric Intake All On One Plate

Newsy (July 30, 2014) — The Center for Science in the Public Interest released its 2014 list of single meals with whopping calorie counts. 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