An specific area of the brain called the fusiform face area (FFA) helps us recognize things, living and nonliving.
Brain scans show that, at least for men, thickness of the cortex in the FFA seems to predict how good men are at knowing a face versus a car, a new study shows.
“It is the first time we have found a direct relationship between brain structure and visual expertise,” says Isabel Gauthier, a psychology professor at Vanderbilt University, who directed the study. “It shows more clearly than ever that this part of the brain is relevant to both face and object recognition abilities.”
Relationships between cortical thickness and other types of processes, such as motor learning and acquisition of musical skills, have been observed before. The relationship seems relatively straightforward: The process of learning to type faster or play a violin causes the neurons in the relevant area of the cortex to make new connections, which causes the cortex to appear thicker.
However, the link between cortical thickness and how well we recognize faces and objects turns out to have a surprising twist.
Gauthier and colleagues measured the ability of 27 men to identify objects from several different categories divided into two groups: living and non-living. They also tested subjects’ ability at recognizing faces.
Using advanced brain-mapping techniques, the researchers were able to pinpoint the exact location of the FFA in each individual and to measure its cortical thickness. When they analyzed the results, the researchers found that the men with thicker FFA cortex performed generally better at identifying non-living objects while those having thinner FFA cortex performed better at identifying faces and living objects.
“It was really a surprise to find that the effects are in opposite directions for faces and non-living objects,” says Gauthier. “One possibility that we are exploring is that we acquire expertise for faces much earlier than we learn about cars, and brain development is quite different earlier versus later in life.”
There are significant sex differences in facial and object recognition, so the researchers would like to repeat the experiment using women to see if this same relation holds true. They would also like to start with a group of non-experts and then track how the thickness of their FFA cortex changes as they undergo the training process to become experts.
The National Science Foundation and National Eye Institute funded the study, which appears in the Journal of Cognitive Neuroscience.
Source: Vanderbilt University