Visual body perception: Towards identifying objective markers of body image disturbance in brain and behaviour

Previous research has shown that the brain processes bodies distinctively from other stimuli. Little research however, has addressed whether visual body perception is modulated by the observer’s conscious experience of their own body (body image). This thesis was therefore dedicated to investigating the relationship between body image disturbance and visual body perception, with the aim of identifying potential objective markers of body image disturbance in brain and behaviour. Initially, the suitability of headless body stimuli was assessed and electroencephalogram (EEG) was employed in order to evaluate the stability of early occipito-parietal (P1, N1) and fronto-central (VPP) visual event-related potentials (ERPs), including body-sensitive effects. A series of studies were then designed to investigate behavioural configural processing mechanisms and the early temporal dynamics of visual body perception (P1, N1, VPP), including the perception of own- and other- identity, in women with and without a history of disorders characterised by body image disturbance, such as eating disorders (EDs) and/or body dysmorphic disorder (BDD). Results confirmed the suitability of headless body stimuli, and of early visual ERP responses and their associated body-sensitivity for investigating visual body processing mechanisms. Further to this, ED participants, not controls, were found to elicit a rapid P1-N1 complex as well as gender-sensitive N1/VPP responses to other women’s bodies; effects which were associated with ED symptomatology. Moreover, results indicated rapid atypical gender-sensitive identity perception in those with EDs/BDD. Finally, behavioural evidence for configural body processing disturbance was found in those recovering from EDs and BDD, as well as in adolescents ‘at risk’ of developing such disorders. It is thus concluded that processes indicative of visual body perception, in both brain and behaviour, present atypically in women who have experienced EDs/BDD. Importantly, rapid visual ERP responses, as well as early gender-sensitive ERP effects, appear to be potential neural markers of ED symptomatology.