Body image alterations in eating disorders patients: a systematic review of neuroimaging studies

Body image distortion (BID) is a common symptom in eating disorders (ED), but its neurobiological underpinnings remain unclear. We aimed to discuss, through a systematic review, BID's neurobiology through studies that used neuroimaging tools in ED patients. The review was developed using the guideline PRISMA, following a 27-step checklist and four-phase flowchart. The following databases were consulted: Lilacs, Scielo, Pepsic, APA/Psycnet, Pubmed, Scopus, Bireme, Cochrane and 1.692 articles were found, 1.95% were included in this research. Anorexia nervosa (AN): Key findings included altered activity in the amygdala, insula, and anterior cingulate cortex, suggesting dysfunctions in emotional response, body perception, and cognitive processes. Additionally, studies have reported changes in functional connectivity between brain regions and reduced gray matter volume in specific areas. Bulimia nervosa (BN): Key findings include alterations in the prefrontal cortex, insula, and anterior cingulate cortex, suggesting dysfunctions in decision-making, impulse control, body perception, and emotional regulation. AN/BN: While AN-R and AN-P showed greater activation in the amygdala, BN patients exhibited greater activation in the prefrontal cortex and occipital and parietal lobes. Both groups presented alterations in functional connectivity and excessive preoccupation with body image, suggesting shared neural underpinnings despite subtype-specific differences. Binge eating disorder (BED): one article exhibits increased activation in the left fusiform body area (FBA) when viewing body stimuli, suggesting an attentional bias towards the body, without corresponding increases in emotional areas. BID in ED seems to be linked to alterations in paralimbic structures (cingulate cortex and insula), the default-mode network, and parietal, temporal, and occipital regions. These brain areas are associated with the subjective self, ego, and perceptual processes. The findings suggest that ED patients may have a perceptual judgment error and excessive self-reference, leading to dysfunctional behaviors as an attempt to resolve this perceptual distortion.