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Release: Immediate
March 31, 2000
UI researchers identify area of the brain involved in assessing others' emotions
IOWA CITY, Iowa -- A frown, a smile, raised eyebrows, pursed lips -- facial expressions can reveal to us a lot about how another person is feeling. But just what enables us to make the connection between facial expressions and emotions?
For some time, researchers have known that the right hemisphere of the brain was important to judge other people's emotions. Now, University of Iowa Health Care investigators have identified specific areas of the brain that aid in emotion assessment of facial expressions.
According to results of a UI study, right somatosensory-related cortices may help people to "put themselves in other's shoes" and think about how they would feel if they were making similar facial expressions. The UI findings appear in the April 1 issue of the Journal of Neuroscience.
Although the role of the amygdala in processing emotions has received considerable attention in scientific study, until the UI investigation, the contribution made by cortical regions within the right hemisphere of the brain had not been well understood.
"Through our investigation, we have discovered some of the neural structures important for empathy," said Ralph Adolphs, Ph.D., UI assistant professor of neurology and lead author of the study. "The surprising finding here is that damage to parts of the brain involved in perceiving one's own body -- like the sensation of touch -- are also important to judge how other people feel."
To come to their conclusions, Adolphs and his colleagues studied 108 patients with focal brain lesions, using three different tasks that assessed the recognition and naming of six basic emotions from facial expressions. The researchers compared the results from the patients with brain damage to 30 control subjects with no history of neurological or psychiatric impairments.
The main experiment involved rating the intensity of basic emotions expressed by faces. All 108 subjects with brain damage and 18 of the control subjects participated in the intensity test. Subjects were shown six blocks of the same 36 facial expressions of basic emotions (six faces of happiness, surprise, fear, anger, disgust and sadness). For each block of the 36 faces, subjects were asked to rate all the faces with respect to the intensity of one of the six basic emotions.
The UI researchers found that subjects who had damage to particular regions of the cortex in the right side of their brains were no longer able to judge, from looking at facial expressions, how other people would feel. The specific regions of the cortex were those parts of the brain that normally process somatosenosry information -- perception of touch, pain, temperature and other body states.
These results are important because they clearly demonstrate for the first time that perception of one's body state -- "feeling" -- is an essential component of processing emotions, Adolphs said. Furthermore, the findings show that judging how other people feel also draws upon the same mechanism.
"To figure out how someone else feels -- for example, from looking at their face -- requires us to imagine what it would feel like if we made that same face," Adolphs said.
This process of imagining a feeling uses the same somatosensory brain structures that people use when they feel their own body, or their own emotional states.
"Our findings help us to understand the structures important for emotion recognition in humans," Adolphs said. "The right somatosensory-related cortices appear to be indispensable for retrieving knowledge about the emotions signaled by facial expressions." In addition to Adolphs, the other investigators from the UI Department of Neurology involved in this study included Antonio Damasio, M.D., professor and head of the department; Hanna Damasio, M.D., professor; Daniel Tranel, Ph.D., professor of neurology and psychology; and Greg Cooper, M.D., Ph.D., assistant professor.
The research was supported by a National Institute of Neurological Disorders and Stroke program project grant, an award from the National Institute of Mental Health, and research fellowships from the Sloan Foundation and the EJLB Foundation.
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