SA41. The Unpredictable Body: Mechanisms Underlying Altered Mapping of the Bodily Self in Schizophrenia

Background: Anomalous bodily experiences, loss of agency, and blurred self-other boundary contribute to the profound self-disturbances that characterize schizophrenia (SZ). Since bodily self-disturbances are present during the prodromal stage, and closely linked to social impairments that determine outcome, it is of great importance to elucidate underlying mechanisms. Our sense of unitary, embodied self depends on continuous spatiotemporal integration and predictive mapping of multisensory signals that places the self in relation to the other in space. To further elucidate origins of self-disturbances, we examined exteroceptive, proprioceptive, and interoceptive functions in relation to abnormal bodily experiences. Methods: Individuals with SZ and matched controls (CO) participated in a series of experiments. To assess embodied emotions, a visual mapping task was used to generate spatial bodily maps of 14 emotions (Nummenmaa et al, 2014). A graphesthesia task was used to test for tactile-visual transformation mapping. Abnormal body boundary was investigated with a tactile-proprioceptive illusion task. Interoceptive awareness was examined with a heart-beat counting task. Subjective bodily self-experiences were captured with a novel picture-based dissociation inventory (Benson et al, 2017). We assessed social isolation in all participants, severity of symptoms in SZ, and schizotypy in CO. Results: Significantly different bodily maps of emotions emerged in SZ compared to CO, with respect to the intensity of felt emotions and the spatial locations of those feelings. SZ were more likely to experience parts of their bodies changing in response to tactile-proprioceptive manipulation and were less accurate in detecting their own internal state (heart beat). Dissociations were present more frequently and intensely in SZ. However, SZ showed intact tactile-visual transformations. Finally, perceived social isolation exacerbated self-disturbances regardless of diagnosis and increased positive symptoms in SZ. Conclusion: Ubiquitous presence of bodily disturbances is likely to impair predictive coding, given the spatiotemporal inconsistencies of the bodily self in relation to the external environment. One’s spatial relationship with the environment may also be further compromised by reduced exposure to the dynamically changing social world. Bodily self-disturbances may interfere with consistent mapping of physiological and interoceptive signals to emotion categories, res