People with anorexia (green areas) and BDD (blue areas) show less activity than healthy people in the brain regions that process “global” information when viewing houses (left) and faces (right).
People with anorexia nervosa and those with body dysmorphic disorder (BDD) have similar abnormalities in their brains that affect their ability to process visual information, a UCLA study reveals. The researchers found that both patient populations had abnormal activity in the visual cortex of the brain during the very first instants when the brain processes “global” information, or images as a whole, as opposed to a tiny detail. This finding suggests that perceptual retraining, a behavioral exercise that attempts to adjust or correct the participant’s balance of global and detailed processing, may be an effective therapy for both disorders.
Previous research on BDD has shown the same type of abnormal activity in the visual cortex, but the UCLA study is the first to link the locations of the abnormal brain activity with time periods beginning as early as one-tenth-of-a-second after an image is viewed. Understanding that timing is significant because it may help scientists determine whether the problem is in lower-level perception that takes place in the visual cortex or elsewhere in higher-level brain systems.
People with anorexia nervosa have a distorted sense of their body weight and shape that can lead to social withdrawal or cardiovascular or electrolyte disturbances severe enough to require hospitalization or even result in death. There are few effective treatments, and many symptoms can be lifelong. Individuals with BDD see themselves as disfigured and ugly — often fixating on minute details of their face or body — even though they look normal to others. Their distress over their appearance can result in depression, anxiety, shame and severe functional impairment that can be severe enough to lead to suicide.
Using functional magnetic resonance imaging to detect regional abnormalities in visual processing and electroencephalography, the researchers assessed the timeline for how the brain processes those signals in subjects with anorexia nervosa and BDD and a control group of healthy individuals as they viewed images of faces and houses.
“Previously, we knew where these visual processing abnormalities existed in the brain in BDD but did not know when they were taking place,” says Jamie Feusner, MD ’99 (RES ’03, FEL ’04, ’06), director of the Obsessive-Compulsive Disorder Program at the Jane and Terry Semel Institute for Neuroscience and Human Behavior at UCLA. “Now, knowing the timing, it is clearer that their perceptual distortions are more likely to be rooted early in their visual systems.”
The researchers found that people with anorexia and those with BDD showed less activity in the regions of the brain that convey primarily global information, although the effect appeared in smaller regions in those with anorexia. Further, the researchers found that individuals with BDD exhibited greater activity in the areas of the brain that process detailed information; the more activity they had in these detail-processing regions, the less attractive they perceived the faces to be, suggesting a connection with distorted perceptions of appearance.
“Anorexia Nervosa and Body Dysmorphic Disorder Are Associated with Abnormalities in Processing Visual Information,” Psychological Medicine, February 5, 2015