Making Meaning Out of What We See

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When your eyes take in light, they see, but they don’t perceive, according to Avniel Ghuman, associate professor of neurological surgery at Pitt. “A camera can take a picture, but it doesn’t know what the picture is of. That’s your brain’s job,” he says.

Ghuman’s Cognitive Neurodynamics Lab studies the neural basis of the visual perception of objects, faces, words and social and affective visual images. And for the past nine years, in collaboration with neurosurgeon Jorge González-Martinez and the University of Pittsburgh Comprehensive Epilepsy Center, Ghuman and his team have been studying epilepsy patients who are undergoing brain surgery. As the patients recover in the hospital, the researchers examine neural activity to better understand how people perceive familiar faces and facial expressions. Their analysis indicates that a region of the visual processing stream—known as the fusiform face area—contributes to most stages of facial identity processing—that is, how you recognize someone. Ghuman and his team also found that the fusiform face area is involved in facial expression processing—like how you interpret someone’s mood. However, many in the field thought the area was only involved in identity processing, says Ghuman.

Ghuman’s research applies to the general population but may also be relevant for people with autism and schizophrenia: “There’s a lot of perceptual deficits that go along with social perception.” He says understanding the circuitry of how the brain actually recognizes those things can tell you something about how they work differently in those patients.