Neural mechanisms of perceptual and affective body-image disturbance during own-body and ideal-body estimation.

Body-image disturbance is a core feature of eating disorders and can predict their development in healthy individuals. There are two components of body-image disturbance: perceptual disturbance (associated with overestimation of body size) and affective disturbance (associated with body dissatisfaction). Previous behavioral studies have hypothesized that attention to particular body parts and negative body-related emotions resulting from social pressure are associated with the respective degrees of perceptual and affective disturbance; however, the neural representations that underlie this hypothesis have not been elucidated. Thus, this study investigated the brain regions and connectivity associated with the degree of body-image disturbance. Specifically, we examined the brain activations associated with participants' estimation of the width of their actual and ideal bodies; we sought to determine which brain regions and functional connectivity from body-related visual processing regions were correlated with the degree of each component of body-image disturbance. The degree of perceptual disturbance was positively correlated with excessive width-dependent brain activations in the left anterior cingulate cortex when estimating one's body size; it was positively correlated with the functional connectivity between the left extrastriate body area and left anterior insula. The degree of affective disturbance was positively correlated with excessive width-dependent brain activation in the right temporoparietal junction and negatively correlated with functional connectivity between the left extrastriate body area and right precuneus when estimating one's ideal body size. These results support the hypothesis that perceptual disturbance is associated with attentional processing, whereas affective disturbance is associated with social processing.