Background and aims
Recent evidence revealed that a negative body image is associated with chronic back pain and pain perception. The body image of a person consists of their perceived physical appearance accompanied by emotions towards that appearance. However, the brain mechanisms underlying these cognitive and affective aspects of body image are still unclear. In the current study, we investigate the neural correlates of three aspects of body image (Self-acceptance, Physical efficacy, Health).

Methods:
24 healthy participants underwent a resting state (fMRI) to explore functional connectivity patterns corresponding to the body image aspects. Furthermore, we applied voxel-based morphometry (VBM) to identify brain regions correlated with body image aspects. Body image was assessed by the German Frankfurt Body Concept Scales [Frankfurter Körperkonzeptskalen (FKKS)]. Pressure pain threshold (PPT) was assessed with a handheld algometer at the hand, back and leg.

Results: Pain threshold was exclusively associated with the body image aspect of physical efficacy. Furthermore, we found a positive correlation between the body image aspect physical efficacy and the functional connectivity between the brain stem and the medial prefrontal cortex (mPFC), which is involved in decisions about self-processing such as personal information. In addition, physical efficacy was negatively correlated with grey matter volume in the supplementary motor cortex (SMC). 

Conclusions:
These data suggest that functional connectivity between brain stem and mPFC may be a neural correlate of body image. Furthermore, our findings provide functional and structural evidence for inter-individual variability and have potential implications for understanding neural mechanisms underlying body image.

THE ASSOCIATION BETWEEN BODY IMAGE AND PRESSURE PAIN THRESHOLD: RESTING-STATE FMRI STUDY