Impaired Brain Activity Underlies Impulsive Behaviors in Women with Bulimia
In the first study of its kind, researchers assessed self-regulatory brain processes in women with bulimia nervosa without using disorder-specific cues, such as pictures of food. The study shows that impaired brain activity underlies the impulsive behaviors in women with bulimia.
Balintfy: In a controlled study of women with and without bulimia nervosa, researchers saw that those with the eating disorder tended to be more impulsive, and generally did not show as much activity in brain areas involved in self-regulation.
Zehr: What's not clear is whether or not it's a cause or a consequence of the disorder.
Balintfy: Dr. Julia Zehr, at the National Institute of Mental Health explains the disorder.
Zehr: Individuals repeatedly eat too much and then engage in purging activities. And those purging activities can be vomiting, or laxatives, and some people also include excessive exercise as one way of compensating for binge eating episodes.
Balintfy: Dr. Zerh adds that binge eating is characterized by feeling a lack of control while eating. She continues that the study shows a biological difference between individuals with bulimia and those without; the difference can lead to research.
Zehr: Where we can look for differences in causation, we can look at different treatment, possibly novel treatments or interventions for the disorder.
Balintfy: The study was conducted by Dr. Rachel Marsh, an NIH-funded scientist from Columbia University. She and her colleagues observed the brain activity of 20 adult women with bulimia, and 20 healthy women of similar age and weight, using functional magnetic resonance imaging.
Marsh: So what we did was we scanned their brains while they were performing a regular cognitive control task or an inhibitory control task.
Balintfy: All of the women viewed a series of arrows presented on a computer screen. Their task was to identify the direction in which the arrows were pointing while the researchers observed their brain activity using the fMRI.
Marsh: So, we're looking at their brain images and what we saw is that the healthy individuals activated large expanses of frontal striatal circuits, and we know that these areas, this system in the brain, mediates the capacity for self-regulatory control, to respond correctly on these trials in terms of this task. The patients with bulimia activated these circuits much, much less, and this was statistically significant. So they performed less accurately on this task and they did not engage the brain circuits that are necessary to perform accurately on the task.
Balintfy: Dr. Marsh adds that implicating a specific brain circuit that is functioning abnormally will help researchers understand what might be causing the impulsivity associated with bulimia.
Marsh: The other thing that we looked at was what was going on in their brains when they were making errors, and so we also saw that when patients with bulimia were making errors on the task they activated these circuits differently than healthy controls.
Balintfy: Researchers are currently conducting further studies on brain functioning in teens with bulimia, which would offer a closer look at the beginnings of their illness. For more information on this study and bulimia nervosa, visit www.nimh.nih.gov. This is Joe Balintfy, National Institutes of Health, Bethesda, Maryland.
About This Audio Report
Reporter: Joe Balintfy
Sound Bite: Dr. Julia Zehr, Dr. Rachel Marsh
Topic: bulimia, bulimia nervosa, binge eating, brain