Contribution of bottom-up and top-down processes to perceptive body image disturbances in adolescent anorexia nervosa

• Applicant: Dr. Ida Wessing
• Subject Area: Personality Psychology, Clinical and Medical Psychology, Methodology ; Clinical Psychiatry, Psychotherapy, Child and Adolescent Psychiatry
• Term: from 2018 to 2022
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 409656150

Anorexia nervosa (AN) is an eating disorder particularly affecting female adolescents. One principal symptom is a disturbance in the way in which one’s own body is experienced. Such a body image disturbance is not only a symptom of AN; it is also a risk factor that predicts the onset of AN as well as relapse and long term outcome. However, it is still under debate what the exact nature of body image disturbance is, and if it is caused predominantly by sociocultural and psychological factors or if it mainly reflects a biological vulnerability. Sociocultural and psychological factors may strongly influence thoughts and emotions towards the body. Disturbances of this cognitive-affective body image, which might be mediated (predominantly) via top-down processes, are well established in AN. Furthermore, even with full insight into their own severe underweight, AN patients typically report perceiving their own body as "too fat". Disturbances of this perceptive body image might reflect a neurobiological vulnerability that possibly underlies or interacts with cognitive-affective components. Importantly, perceptive body image disturbances implicate a stronger influence of bottom-up processes. To date, the perceptive body image has been studied comparatively little in AN. AN patients clearly overestimate their own body size. Moreover, when viewing body pictures, AN patients show increased activity in emotion-related brain regions, related to the cognitive-affective body image, and reduced activity in visual and somatosensory regions, related to the perceptive body image. Consistent with a perceptive dysfunction, AN patients show also disturbances of basic visual and tactile perception. Overall though, results are inconsistent and prior studies mostly neglected the relative contribution of bottom-up and top-down processes. To fill this gap, we will investigate visual and tactile body perception in AN using parallel electro- and magnetoencephalography (EMEG). These temporally high-resolution methods differentiate between early bottom-up and late top-down processes, and beyond that, as combined EMEG source reconstructions provide good spatial resolution, differentiate between brain areas associated with these processes. The use of source reconstructions in underweight AN patients has specific methodical implications: The severe underweight may be accompanied by brain atrophy, which can have profound effects on the EMEG. Therefore, source reconstructions will be corrected using structural MRI scans and possible effects of brain atrophy will be compared longitudinally in the underweight and weight-recovered condition. The availability of MEG, EEG and MRI devices and our (the applicant’s and the project group’s) clinical and methodical expertise excellently position the planned project for success. Upon completing this research, we will have a better understanding of the perceptive dysfunctions that may underlie body image disturbances in AN.

• DFG Programme: Research Grants
• Co-Investigators: Professor Dr. Markus Junghöfer; Professor Dr. Carsten Hermann Wolters