Navigation Links
Just another pretty face: Dartmouth professor investigates neural basis of prosopagnosia
Date:2/1/2012

For Bradley Duchaine, there is definitely more than meets the eye where faces are concerned.

With colleagues at Birkbeck College in the University of London, he is investigating the process of facial recognition, seeking to understand the complexity of what is actually taking place in the brain when one person looks at another.

His studies target people who display an inability to recognize faces, a condition long known as prosopagnosia. Duchaine is trying to understand the neural basis of the condition while also make inferences about what is going wrong in terms of information processingwhere in the stages that our brains go through to recognize a face is the system breaking down. A paper published in Brain details the most recent experimental results.

"We refer to prosopagnosia as a 'selective' deficit of face recognition, in that other cognitive process do not seem to be affected," explains Duchaine, an associate professor of psychological and brain sciences. "[People with the condition] might be able to recognize voices perfectly, which demonstrates that it is really a visual problem. In what we call pure cases, people can recognize cars perfectly, and they can recognize houses perfectly. It is just faces that are a problem."

The condition may be acquired as the result of a stroke, for example. But in the recent study, Duchaine focused on developmental prosopagnosia, in which a person fails to develop facial recognition abilities.

"Other parts of the brain develop apparently normally," Duchaine says. "These are intelligent people who have good jobs and get along fine but they can't recognize faces."

The primary experimental tool in this experiment was the electroencephalogram (EEG), which has the advantage of providing excellent temporal resolutionpinpointing the timing of the brain's electrical response to a given stimulus.

Duchaine and his colleagues placed a series of electrodes around the scalps of prosopagnosics and showed them images of famous faces and non-famous faces, recording their responses. As expected, many of the famous faces were not recognized.

They found an electrical response at about 250 milliseconds (ms) after seeing the faces. Among the control group of non-prosopagnosics, a real difference was observed between their responses to famous and non-famous faces. In half the prosopagnosics there was not. Surprisingly, however, in the other half of the prosopagnosic test subjects they did find a difference.

"On the many trials where half failed to categorize a famous face as familiar, they nevertheless showed an EEG difference around 250ms after stimulus presentation between famous and non-famous faces like normal subjects do. Normal subjects also show a difference between famous and non-famous about 600ms after presentation, but the prosopagnosics did not show this difference," Duchaine observes.

This pattern of results suggests the prosopagnosics unconsciously recognized the famous faces at an early stage (250ms) but this information was lost by the later stage (600ms). Duchaine concludes that even though they are not consciously aware that this is a famous face, some part of their brain at this stage in the process is aware and is recognizing that face, a phenomenon termed covert face recognition.

He suggests that the other half of the prosopagnosics, who showed no difference between responses at 250ms, were experiencing a malfunction in their face processing system already at this early stage suggesting a different type of prosopagnosia.

"The temporal lobe contains a number of face processing areas, so you can imagine there are many different ways that this system can malfunction. Not only can an area not work, connections between areas might not work yielding probably dozens of these different variants of this condition," he surmises.

Covert recognition has been demonstrated in prosopagnosia acquired through brain damage, but Duchaine's work is the first convincing demonstration of covert recognition in developmental prosopagnosia, the much more common form.


'/>"/>
Contact: Justin Anderson
justin.anderson@dartmouth.edu
603-646-3015
Dartmouth College
Source:Eurekalert  

Related biology news :

1. Another fisheries commission throws the science overboard in tuna decision, WWF says
2. Another reason to drink a nice cup of shade-grown joe
3. Cancer: Another step towards medication
4. Desert woodrats switch one dietary poison for another
5. Desert woodrats switch one dietary poison for another
6. The first DFG research centers to be funded for another four years
7. Another JDRF partner moves research forward with collaboration agreement for diabetes treatment
8. Ability to literally imagine oneself in anothers shoes may be tied to empathy
9. Why one way of learning is better than another
10. An answer to another of lifes big questions
11. Genetically-modified mice reveal another mechanism contributing to heart failure
Post Your Comments:
*Name:
*Comment:
*Email:
Related Image:
Just another pretty face: Dartmouth professor investigates neural basis of prosopagnosia
(Date:2/3/2016)... , February 4, 2016 --> ... SEK 1,351.5 M (105.0), up 1,187% compared with fourth quarter of 2014. ... to SEK 517.6 M (loss: 30.0). Earnings per share increased ... was SEK 537.4 M (neg: 74.7). , ... Revenues amounted to SEK 2,900.5 M (233.6), up 1,142% compared with 2014. ...
(Date:2/3/2016)... Feb. 3, 2016 ... of the "Emotion Detection and Recognition ... and Others), Software Tools (Facial Expression, Voice ... Users,and Regions - Global forecast to 2020" ... --> http://www.researchandmarkets.com/research/d8zjcd/emotion_detection ) has announced the ...
(Date:2/2/2016)... 2, 2016 Checkpoint Inhibitors for Cancer ... Are you interested in the future of ... checkpoint inhibitors. Visiongain,s report gives those predictions to ... national level. Avoid falling behind in data ... and revenues those emerging cancer therapies can achieve. ...
Breaking Biology News(10 mins):
(Date:2/9/2016)... , Feb. 9, 2016  Regenicin, Inc. (OTC ... specializing in the development and commercialization of regenerative ... tissues and organs, recently reported the Company,s operating ... quarter of 2016. Lonza America , ... 2015 fiscal year in the process of consummating ...
(Date:2/9/2016)... ... February 09, 2016 , ... The American Academy of ... it is offering its 2016 AAT Member Certification Qualification Course for Technicians via a ... the webinar, which will include a detailed review of hardware, software, and camera setup/operations, ...
(Date:2/9/2016)... and LONDON , February 9, 2016 ... bio tech replace paper and protect IP ... electronic laboratory notebook (ELN) will be rolled out in ... research and development (R&D) and protect valuable IP. Users will ... follow a specific researcher or experiment as part of the ...
(Date:2/8/2016)... , Feb. 8, 2016 Should antibiotic ... bone cement products to prevent infection after standard total ... the experts at ECRI Institute have been fielding a ... or Fighting Your Bottom Line?" --> ... Bottom Line?" --> While there ...
Breaking Biology Technology: