Patricia S. Goldman-Rakic, Ph.D., of neurobiology, and her colleagues have pinpointed an area of the brain that retrieves information about faces and facial expressions from memory. Their findings were reported in the Nov. 7 issue of the journal Science.
The research team showed macaque monkeys pictures of human faces and objects, and measured the electrical impulses in different areas of the brain. Research results showed that neurons clustered in an area of the inferior prefrontal cortex responded only to pictures of faces and to no other stimuli. The team further found that the prefrontal cortex was able to maintain information about the faces even after the stimuli were removed.
Scientists know that the prefrontal cortex is the most advanced part of the human brain and is responsible for cognitive functions such as memory, reasoning, mental computation and languages, but it has been unclear how the prefrontal cortex processes information. "This study has revealed that information related to faces is processed in a specific region of the prefrontal cortex," says Dr. Goldman-Rakic, the study's principal investigator. "This shows not only that the prefrontal cortex is modular and specialized by domain, but that each of its neurons has a dedicated function, since individual neurons code individual types of information–for example, different faces."
Past studies of brain function have focused mostly on sensory and motor areas, which have been found to be modular and specialized. Some scientists have theorized that the prefrontal cortex might function in a different way. Seamas P. Ó Scalaidhe, Ph.D., associate research scientist in neurobiology and the study's first author, points out that in this respect, the organization of the prefrontal cortex resembles that of other brain areas.
"Our study indicates that the pre-frontal cortex is modular, like other brain areas that have been more closely examined," says Dr. Ó Scalaidhe. "This research has brought us closer to understanding how the higher centers of the human brain work."
Dr. Goldman-Rakic's team included Dr. Ó Scalaidhe and Fraser A.W. Wilson, Ph.D., now an assistant professor at the University of Arizona. The National Institute of Mental Health and the McDonnell Foundation funded the study.