Apr. 8, 2003 A child falls from his bicycle and his father winces. A bride says "I do" and the maid of honor grins from ear to ear. A mother frowns with displeasure and her infant son frowns back.
UCLA neuroscientists using functional magnetic resonance imaging (fMRI) are the first to demonstrate that empathetic action, such as mirroring facial expressions, triggers far greater activity in the emotion centers of the brain than mere observation.
Reporting in the April 15 edition of the peer-reviewed Proceedings of the National Academy of Science, the researchers also identified the brain's oval-shaped insula as a key to translating active imitation of others' feelings into meaningful emotion.
The findings explain why humans vary in their ability to understand the pain, joy and anger of others, and how damage to this neural circuit might impair the ability to empathize with the emotions of others, as often seen in patients with autism, a socially isolating psychiatric disease.
"For years scientists have observed the reflexive mimicking of a wince when someone suffers a painful injury, and the infectious nature of joy or anger," said Dr. Marco Iacoboni, a neuroscientist affiliated with the UCLA Neuropsychiatric Institute and the UCLA Brain Research Institute who led the study.
"Our findings show for the first time how these reflexive facial expressions prompt our brain to heighten our empathy for the feelings of others," said Iacoboni, an associate professor-in-residence of psychiatry and biobehavioral sciences at the David Geffen School of Medicine at UCLA. "Understanding the mechanism for regulating empathy explains the continuum of empathy in humans, and also moves us closer toward identifying ways to better control our emotional responses and reverse impairment caused by brain injury, illness and age. This research is especially important for understanding core deficits in autism, such as imitation and empathic resonance."
Using the resources of UCLA's Ahmanson-Lovelace Brain Mapping Center, the researchers evaluated the neural response of 11 research subjects to a series of pictures depicting six emotions -- happiness, sadness, anger, surprise, disgust and fear. The subjects observed the pictures through magnetic-compatible goggles and were asked either to imitate and internally generate the target emotion in the picture, or simply to observe.
The researchers found that imitation and observation of emotions activated a largely similar network of brain activity. Within this network, composed by motor areas as well as the inferior frontal cortex, superior temporal cortex, insula and amygdala, researchers found increased activity during imitation than during observation of emotions. The cortex is the outer layer of the brain.
Previous brain studies from Iacoboni's lab had discovered that the superior temporal and inferior frontal cortices are critical areas for imitation. These areas are connected to the limbic system -- the brain's emotion centers -- via the insula. Therefore, the researchers surmise the insula plays a fundamental role in regulating emotional content, perhaps acting as a critical relay in translating empathetic imitation into emotion.
The study was funded by the Brain Mapping Medical Research Organization, the Brain Mapping Support Foundation, the Pierson-Lovelace Foundation, The Ahmanson Foundation, the Tamkin Foundation, the Jennifer Jones-Simon Foundation, the Capital Group Companies Charitable Foundation, the Robson Family, the Northstar Fund and the National Center for Research Resources.
In addition to Iacoboni, other researchers involved in the study included Laurie Carr, now at Michigan State University, and Marie Charlotte Dubeau of the Ahmanson-Lovelace Brain Mapping Center at the UCLA Neuropsychiatric Institute; Dr. John C. Mazziotta, director of the Ahmanson-Lovelace Brain Mapping Center and professor and chair of neurology at UCLA's David Geffen School of Medicine; and Gian Luigi Lenzi of the Department of Neurological Sciences at the University "La Sapienza," in Rome, Italy.
The UCLA Neuropsychiatric Institute is an interdisciplinary research and education institute devoted to the understanding of complex human behavior, including the genetic, biological, behavioral and sociocultural underpinnings of normal behavior, and the causes and consequences of neuropsychiatric disorders. In addition to conducting fundamental research, the institute faculty seeks to develop effective treatments for neurological and psychiatric disorders, improve access to mental-health services, and shape national health policy regarding neuropsychiatric disorders.
The UCLA Brain Research Institute fosters and improves interdisciplinary collaborations in all aspects of neuroscience, from molecules to the mind, from the laboratory bench to the patient's bedside. This work has increasingly permitted the identification of pathogenic mechanisms and the creation of new therapeutic approaches.
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