Neural Dysfunction of Interoception in Adolescents Diagnosed With Anorexia Nervosa

Individuals with anorexia nervosa (AN) have aberrant feeding behavior, disturbances of emotionality and impulse control, and have high rates of relapse after weight restoration (Carter et al., 2004; Halmi et al., 2003). There is no proven treatment that reverses symptoms. Although imaging studies in individuals recovered from AN (REC AN) suggest that these symptoms are related to dysfunction of the striatal, insular, and prefrontal areas, less is known about the biology of these core symptoms in currently ill individuals (ILL AN). This application will use blood oxygen level-dependent (BOLD) functional magnetic resonance imaging (fMRI) to examine neural substrates underlying appetitive, reward, and cognitive dysregulation in ill AN. We will study 22 adolescent women currently ill with AN and 22 healthy adolescent control women (CW), all of whom are 14 to 18 years old.

The specific aims of the project are:

AIM 1: The anterior insula (AI), orbitofrontal cortex (OFC), and associated regions integrate sensory/hedonic aspects of taste and interoceptive awareness in the service of homeostasis. We hypothesize that restricted eating and weight loss occur in AN because a palatable food elicits little reward.

AIM 2: Little in life is rewarding to individuals with AN aside from weight loss, and they tend to be overconcerned with future consequences. We predict that ill AN will show an inability to discriminate positive and negative feedback reflecting aberrant anterior ventral striatum (AVS) limbic function.

AIM 3: AN tend to be rigid, inflexible and behaviorally inhibited. We will use a stop task (Band et al., 2003; Logan et al., 1984; Matthews et al., 2005) to characterize the neural substrates of inhibitory motor control. We hypothesize that ill AN, relative to CW, will show a demand-specific alteration of a fronto-subthalamic circuit that is necessary for motor inhibition (Aron et al., 2004).