Navigation Links
Just another pretty face: Dartmouth professor investigates neural basis of prosopagnosia

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
Dartmouth College

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:
Related Image:
Just another pretty face: Dartmouth professor investigates neural basis of prosopagnosia
(Date:11/20/2015)... OXFORD, Connecticut , November 20, 2015 ... biometric authentication company focused on the growing mobile commerce ... its CEO, Gino Pereira , was recently interviewed ... The interview will air on this weekend on ... Bloomberg Latin America . --> NXTD ) ...
(Date:11/18/2015)... 2015  As new scientific discoveries deepen our understanding ... healthcare providers face challenges in better using that knowledge ... addition, as more children continue to survive pediatric cancer, ... old age. John M. Maris, M.D ., ... Philadelphia (CHOP) . --> John M. ...
(Date:11/17/2015)... -- Paris , qui s,est ... Paris , qui s,est tenu du 17 ... de l,innovation biométrique, a inventé le premier scanner couplé, ... la même surface de balayage. Jusqu,ici, deux scanners étaient ... empreintes digitales. Désormais, un seul scanner est en mesure ...
Breaking Biology News(10 mins):
(Date:11/24/2015)... 2015 --> ... "Oligonucleotide Synthesis Market by Product & Services (Primer, Probe, ... DNA, RNAi), End-User (Research, Pharmaceutical & Biotech, Diagnostic Labs) ... market is expected to reach USD 1,918.6 Million by ... CAGR of 10.1% during the forecast period. ...
(Date:11/24/2015)... LEXINGTON, Massachusetts , November 24, 2015 ... Officer, will participate in the Piper Jaffray 27 th Annual ... on Tuesday, December 1, 2015, at 8:30 a.m. EST (1:30 p.m. ... Poulton , Chief Financial Officer, will participate in the Piper Jaffray ... City , NY on Tuesday, December 1, 2015, at 8:30 ...
(Date:11/24/2015)... Nov. 24, 2015 /PRNewswire/ - Aeterna Zentaris Inc. ... that the remaining 11,000 post-share consolidation (or 1,100,000 ... (the "Series B Warrants") subject to the previously ... November 23, 2015, which will result in the ... effect to the issuance of such shares, there ...
(Date:11/24/2015)... , ... November 24, 2015 , ... InSphero AG, the ... cell culture models, has promoted Melanie Aregger to serve as Chief Operating Officer. ... served on the management team and was promoted to Head of InSphero ...
Breaking Biology Technology: