Face recognition research at Ben Gurion University.
(photo credit: DANI MACHLIS/BGU)
A way to better diagnose a rare condition in which people are born with difficulty in recognizing faces – even their own – has been developed by scientists at Ben-Gurion University of the Negev.
The findings speed the development of imaging-based tools to diagnose congenital prosopagnosia (CP – from the Greek for “face” and “not knowing”). The same approach could also be used to investigate the basis of other neurodevelopmental disorders that are thought to involve abnormal communication within brain networks, including the much more common developmental dyslexia.
Human babies prefer to look at faces and pictures of faces more than any other object or pattern. A recent study found that even fetuses in the womb will turn their heads towards dots of light shone through the mother’s skin if the dots broadly resemble a face.
Brain imaging studies show that face recognition depends on the coordinated activity of multiple brain regions. A core set of areas towards the back of the brain processes the visual features of faces, while regions elsewhere process more variable features such as emotional expressions.
About 2% of the population suffer from CP. As they have no obvious anatomical abnormalities in the brain and scans reveal normal activity in core regions of the face-processing network, what causes the problem is a mystery.
One possibility is that the condition reflects differences in the number of connections (or “connectivity”) among the brain regions within the face-processing network.
To test this hypothesis, the Beersheba researchers compared connectivity in individuals suffering from CP to that of healthy volunteers. Among the healthy group, an area of the network called the anterior temporal cortex was highly connected to many other face-processing regions – that is, it acted as a face-processing hub. In those with CP, this hub-like connectivity was missing. Instead, a number of core regions involved in processing the basic visual features of faces were more highly connected to one another. The greater this “hyper-connectivity”, the better were the individual’s face processing abilities.
“This study provides a bird’s-eye view of the face network that sheds new light on critical questions, such as what aspects of the network architecture underlie normal face representation and what aspects of the network are compromised when face perception is impaired,” explained primary BGU investigator Prof. Galia Avidan.