Bulimia and the Vaso-Vagal Reflex

This is another post in Sci’s investigation into the current studies being performed on eating disorders, particularly binge eating and bulimia. Usually I try to focus on the dysregulation of reward-related systems in these disorders, but this paper will be a little different.
Faris et al. “De-Stabilization of the Positive Vago-Vagal Reflex in Bulimia Nervosa” Physiology and Behavior, 2008.
It’s kind of in the nature of an eating disorder that there aren’t any really funny pictures or something that Sci can put in here.
So before we go forward, here’s a kitten.

(ahhhhh.)

Anorexia, Dopamine, and Experimental Confounds

We are now continuing on Sci’s new found, somewhat relentless search into the relationship between eating disorders such as binge eating, bulimia, and anorexia, and reward systems that are usually associated with things like drug addiction.
And today I found a human study that looks a little…interesting. For a lot of reasons. Let’s talk dopamine receptors, shall we?
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Frank et al. “Increased Dopamine D2/D3 Receptor Binding After Recovery from Anorexia Nervosa Measured by Positron Emission Tomography and [11C]Raclopride” Biological Psychiatry, 2005.
This one’s going to require some background. Let’s talk about dopamine and dopamine receptors.

Binge Eating, Bulimia, and Reward Sensitivity

You all may remember that Sci’s recent posts have focused on eating, overeating, and dopamine. Today, Sci continues this trend. Honestly, she couldn’t stop thinking about it. How is overeating like addiction? How is it different? And so she began to look up a bunch of papers on binge eating and dopamine.
I was particularly interesting in the changes in food intake and reward associated responses in people with eating disorders like bulimia nervosa and anorexia nervosa. There are many hypotheses as to why these eating disorders exist, ranging from problems with society (which can certainly contribute to the incidence of the disorders), to hypotheses of obsessive control akin to the compulsions seen with OCD, to increased sensitivity to reward, to decreased sensitivity to reward.
This increased/decreased sensitivity to reward (some people have seen decreased sensitivity to reward in rats, along with increased self-administration of pleasurable things, but what this actually translates to in humans can be difficult to interpret) was particularly interesting, and so Sci was very glad when she came across this study.
Schienle et al. “Binge-Eating Disorder: Reward Sensitivity and Brain Activation to Images of Food “, Biological Psychiatry, 2008.

(Sci will admit her brain activated really hardcore looking at that. Soooo much chocolate…)