Researchers develop model on how brain reward response may impact anorexia nervosa

July 26, 2018

AURORA, Colo. (July 26, 2018) - Researchers at the University of Colorado Anschutz Medical Campus have found that the brain's response to taste stimuli is linked to high anxiety and a drive for thinness that could play a role in driving anorexia nervosa.

The study was published last week in the journal JAMA Psychiatry.

The researchers, led by Dr. Guido Frank, MD, associate professor of psychiatry and neuroscience at the University of Colorado School of Medicine, monitored a large group of patients with anorexia nervosa as they tasted sugar during brain imaging.

They found their brain response was higher than those in the control group, representing a biological marker for the illness. At the same time, this brain response was related to high anxiety and less weight gain for those being treated for anorexia nervosa.

Frank found that as these patients restricted their diet, a brain reward circuit associated with the neurotransmitter dopamine becomes more active but also triggers anxiety. This makes food avoidance worse and perpetuates the often deadly disease.

"When you lose weight your brain reward response goes up," said Frank. "But instead of driving eating, we believe it elevates anxiety in anorexia nervosa, which makes them want to restrict more. This becomes then a vicious cycle."

Using brain scans, the researchers examined 56 female adolescent and young adults with anorexia nervosa between the ages of 11 and 21 and 52 healthy control participants of the same age. They all learned to associate colored shapes with either getting or not getting a sugary solution. Sometimes when they expected sugar they got nothing, and sometimes when they didn't expect sugar they received it.

Those with the eating disorder responded more strongly to the unexpected getting or not getting of sugar water, perhaps due to the release of dopamine.

The researchers found that the higher the brain response, the higher the harm avoidance in those with anorexia nervosa was. Harm avoidance is an anxiety measure for excessive worrying and fearfulness. In these patients, it pushes the drive for thinness and furthers body dissatisfaction.

Frank discovered that the higher the brain response, the lower the weight gain during treatment.

This brain reward response acted on the hypothalamus, which stimulates eating, in the anorexia nervosa group. The researchers hypothesized that this could make it possible to override and fend off signals to eat.

"An enhanced dopamine reward system response is an adaptation to starvation," the study said. "Individuals vulnerable to developing anorexia nervosa could be particularly sensitive to food restriction and adaptations of reward response during the [mid-adolescence] development period."

According to Frank, anorexia nervosa behavior could alter the brain circuits and impact its taste-reward processing mechanisms. Those who are already worried about shape and weight become even more concerned. And a strong response that says "feed me" might be overwhelming and trigger more food restriction instead of eating.

The study noted that while most people like sweet tasting things, those with eating disorders associate the taste with weight gain and try to avoid it. Frank found that the brain activation among the anorexia group was inversely connected with any pleasant experience of eating sugar.

"Our data raise the possibility that adolescents with anorexia nervosa in this study were negatively conditioned to sweet taste and may have developed an inverse association with dopamine release across the larger (brain) reward circuitry," the study said.

Frank believes these insights could lead to new treatments for eating disorders.

"I hope we can use these findings to manipulate these biomarkers and design better treatments for this often-deadly disease," he said.
-end-
The study's coauthors include: Marisa C. DeGuzman, BA, BS; Megan E. Shott, BS; Mark L. Laudenslager, PhD; Brogan Rossi, BS, all from the University of Colorado Anschutz Medical Campus. And Tamara Pryor, PhD, of Eating Disorder Care, Denver, Colorado.

University of Colorado Anschutz Medical Campus

Related Dopamine Articles from Brightsurf:

Dopamine surge reveals how even for mice, 'there's no place like home'
''There's no place like home,'' has its roots deep in the brain.

New dopamine sensors could help unlock the mysteries of brain chemistry
In 2018, Tian Lab at UC Davis Health developed dLight1, a single fluorescent protein-based biosensor.

Highly sensitive dopamine detector uses 2D materials
A supersensitive dopamine detector can help in the early diagnosis of several disorders that result in too much or too little dopamine, according to a group led by Penn State and including Rensselaer Polytechnic Institute and universities in China and Japan.

Dopamine neurons mull over your options
Researchers at the University of Tsukuba have found that dopamine neurons in the brain can represent the decision-making process when making economic choices.

Viewing dopamine receptors in their native habitat
A new study led by UT Southwestern researchers reveals the structure of the active form of one type of dopamine receptor, known as D2, embedded in a phospholipid membrane.

Significant differences exist among neurons expressing dopamine receptors
An international collaboration, which included the involvement of the research team from the Institut de Neurociències of the UAB (INC-UAB), has shown that neurons expressing dopamine D2 receptors have different molecular features and functions, depending on their anatomical localization within the striatum.

How dopamine drives brain activity
Using a specialized magnetic resonance imaging (MRI) sensor that can track dopamine levels, MIT neuroscientists have discovered how dopamine released deep within the brain influences distant brain regions.

Novelty speeds up learning thanks to dopamine activation
Brain scientists led by Sebastian Haesler (NERF, empowered by IMEC, KU Leuven and VIB) have identified a causal mechanism of how novel stimuli promote learning.

Evidence in mice that childhood asthma is influenced by the neurotransmitter dopamine
Neurons that produce the neurotransmitter dopamine communicate with T cells to enhance allergic inflammation in the lungs of young mice but not older mice, researchers report Nov.

Chronic adversity dampens dopamine production
People exposed to a lifetime of psychosocial adversity may have an impaired ability to produce the dopamine levels needed for coping with acutely stressful situations.

Read More: Dopamine News and Dopamine Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.