Attenuation of self-produced touch in the posterior insula reflects body image disturbances in anorexia nervosa

Body image disturbance (BID) is a core feature of anorexia nervosa (AN), encompassing multimodal distortions in bodily self-perception. Affective touch, a gentle, emotionally salient tactile stimulus, is implicated in body ownership but has not been extensively studied in AN. Affective touch is processed in the insula, an area involved in interoception and bodily self-awareness which has been shown to be altered both structurally and functionally in AN. This study explored the neural mechanisms underlying BID by examining how individuals with AN process self-produced affective touch. Women with AN (n=44) and age-matched healthy controls (HC, n=40), participated in a self-other-object touch task during functional brain imaging and filled out questionnaires related to body image and eating disorder symptomatology. During self-touch, individuals with AN exhibited increased activation in the right posterior insula compared to object-touch, whereas HC did not. This insular activation correlated positively with BID measures in AN but negatively in HC, suggesting divergent processing of self-related tactile input. Here we identify the posterior insula as a potential neural marker of disturbed embodiment and demonstrate that the sensory processes which typically stabilize body ownership may exacerbate distorted body perception in AN. Broadening BID research beyond the visual modality opens new avenues for translational research and treatment.