Los Angeles, Dec. 11, 2006 -- Researchers in Southern California have isolated brain regions that respond selectively to the cues of gender, ethnicity and identity in faces. Using a novel adaptation technique, they found evidence for neurons that are selectively tuned for gender, ethnicity and identity cues in an area not previously thought to be associated with face processing. Led by researchers at the University of Southern California (USC), the work is a collaboration between USC, the Salk Institute for Biological Studies, and the University of California at San Diego (UCSD). The findings appear Dec. 11 in the Proceedings of the National Academy of Sciences.
"When looking at a face, its gender and ethnicity tends to be the first thing we notice," says Ione Fine, Ph.D., assistant professor of ophthalmology at the Keck School of Medicine of USC and the principal investigator of the study. "We become sensitive to these cues remarkably early in life. If you look at how pre-school children classify faces you find that these very young children pay attention to gender, ethnicity and age. In contrast, small children barely notice if a person is wearing eyeglasses. We wanted to see what was happening in the brain."
The experimenters relied on an adaptation technique. Over a period of three minutes subjects were adapted to a series of male Asian and female Caucasian face images. The researchers then interposed occasional female Asian and male Caucasian face images and measured how the appearance of these faces was altered by the previous adaptation. They found that adaptation altered the appearance of faces- adaptation to male Asian and female Caucasian faces made male faces appear more Caucasian and female faces appear more Asian.
The authors then used functional magnetic resonance imaging to measure brain responses using the same paradigm. This allowed them to isolate brain responses driven by very selective neurons tuned for both e
Contact: Jon Weiner
University of Southern California