Morphometric Evidence of a U-Shaped Relationship Between Loss Aversion and Posterior Insular/Somatosensory Cortical Features.

Neuroeconomic findings show that interoceptive sensitivity contributes to the typical overweighting of prospective losses over gains known as "loss aversion." Whether the latter is related to the morphometric properties of the insula-a key node for interoception-remains, however, debated, due to previous conflicting evidence of both positive and negative correlations between their respective metrics. We combined a well-established behavioral modeling approach with a comprehensive morphometric protocol to explore both a linear and quadratic relationship between loss aversion and distinct voxel-based and surface-based cortical features in a sample of 208 healthy young individuals. Both univariate and multivariate analyses highlighted a positive quadratic (i.e., U-shaped) relationship between loss aversion and distinct morphometric features of the posterior insula and somatosensory-parietal cortex. These results first suggest that previous inconsistent findings might reflect methodological differences across studies, facilitating the detection of either the descending or ascending sectors of a U-shaped relationship between loss aversion and structural features. Moreover, they provide novel insights into the interoceptive modulation of choice-related evaluations guiding decision-making towards or away from loss avoidance, thus paving the way to studies investigating alterations of this mechanism in neuro-psychiatric conditions and its susceptibility to different types of intervention including neuromodulation.