The prefrontal cortex is underactive in bulimia, leading to impulsivity, while overactive in anorexia.

“Prefrontal cortex is involved in this analysis of duration, path, and outcome. Duration, path, and outcome is how we avoid impulsivity. It's how we think, okay, if this, then that, if that, then this. You can imagine how for the obsessive compulsive or for the um anorexic, these are circuits that are overactive. For the bulimic, this is the circuit that's going to essentially be underactive. So really the polar opposite of what you see in anorexia. So this lack of impulsivity implies a lack of prefrontal control, what we call top down control.”