'Connection error' in the brains of anorexics

Network for body processing: When people look at body images, the visual information first enters in the central occipital lobe (mOC). The “fusiform body area” (FBA) and the “extrastriate body area” (EBA) then process the images further. In anorexic women, the connection from the mOC to the FBA is unaffected (black arrow). However, the FBA and EBA do not work normally together in the left hemisphere (red arrow). Credit: Boris Suchan

When people see pictures of bodies, a whole range of brain regions are active. This network is altered in women with anorexia nervosa. In a functional magnetic resonance imaging study, two regions that are important for the processing of body images were functionally more weakly connected in anorexic women than in healthy women. The stronger this "connection error" was, the more overweight the respondents considered themselves.

"These alterations in the brain could explain why women with anorexia perceive themselves as fatter, even though they are objectively underweight" says Prof. Dr. Boris Suchan of the Institute of at the Ruhr-Universität. Together with Prof. Dr. Dietrich Grönemeyer (University of Witten-Herdecke), Prof. Dr. Silja Vocks (University of Osnabrück) and other colleagues, the Bochum researchers report in the journal Behavioural Brain Research.

Anorexics misperceive their body shape

The researchers tested ten anorexic and fifteen healthy women of similar age. To start with, all the women judged on the computer which of several different silhouettes corresponded best to their own . Ten control subjects who did not participate in the MRI scan answered the same question by matching a photo of the test subject to the right silhouette. Both healthy and anorexic women estimated their body shape differently than outsiders: healthy subjects rated themselves as thinner than the control subjects. Anorexic women on the other hand perceived themselves to be fatter than the control subjects did.

Brain areas for body perception examined with MRI

In , the researchers then recorded the brain activity of the 25 participants while they observed photos of bodies. Above all, they analysed the activity in the "fusiform body area" (FBA) and the "extrastriate body area" (EBA), because previous studies showed that these are critical for the perception of bodies. To this end, the neuroscientists from Bochum calculated the so-called effective connectivity between the FBA and EBA in both hemispheres. This is a measure of how much the activity in several is temporally correlated. A high degree of correlation is indicative of a strong connection.

Brains of anorexics structurally and functionally altered

The connection between the FBA and EBA was weaker in women with than in healthy women. In addition, the researchers found a negative correlation between the EBA-FBA connection in the left hemisphere and the misjudgement of body weight: the weaker the effective connectivity between the EBA and FBA was, the fatter the subjects with anorexia falsely estimated themselves to be. "In a previous study we found that there are structural changes in the brains of patients with anorexia", says Boris Suchan. They have a lower density of nerve cells in the EBA. "The new data shows that the network for body processing is also functionally altered." The EBA, which has a lower cell density in anorexics, is also the area that stood out in the connection analysis: it receives reduced input from the FBA. "These changes could provide a mechanism for the development of anorexia", says Suchan.

More information: Suchan, B. et al. Reduced connectivity between the left fusiform body area and the extrastriate body area in anorexia nervosa is associated with body image distortion, Behavioural Brain Research, 2012. DOI: 10.1016/j.bbr.2012.12.002

add to favorites email to friend print save as pdf

Related Stories

Marking anorexia with a brain protein

Jun 23, 2009

Eating disorders are frequently seen as psychological or societal diseases, but do they have an underlying biological cause? A new study shows that the levels of a brain protein differ between healthy and anorexic women.

Why anorexic patients cling to their eating disorder

Aug 03, 2009

Anorexic patients drastically reduce food intake and are often not capable of changing their behavior. This can lead to life-threatening weight loss. Using MRI technology, scientists at Heidelberg University Hospital have ...

Recommended for you

Discovery hints at why stress is more devastating for some

1 hour ago

Some people take stress in stride; others are done in by it. New research at Rockefeller University has identified the molecular mechanisms of this so-called stress gap in mice with very similar genetic backgrounds—a ...

Family dinners reduce effects of cyberbullying in adolescents

13 hours ago

Sharing regular family meals with children may help protect them from the effects of cyberbullying, according to a study by McGill professor Frank Elgar, Institute for Health and Social Policy. Because family meal times represent ...

The Edwardians were also fans of brain training

19 hours ago

Brain-training programmes are all the rage. They are part of a growing digital brain-health industry that earned more than US$1 billion in revenue in 2012 and is estimated to reach US$6 billion by 2020. The extent to which they actually improve brain function re ...

Report advocates improved police training

Aug 29, 2014

A new report released yesterday by the Mental Health Commission of Canada identifies ways to improve the mental health training and education that police personnel receive.

User comments