Diffusion connectometry reveals white matter substrates of individual differences in loss aversion

While neural responses in striatal, limbic and somatosensory regions are known to track individual differences in loss aversion, a system-level view of its neural basis is still lacking, and, in particular, a possible association with white matter (WM) microstructural organization remains unexplored. We investigated the relationship between behavioural loss aversion and fractional anisotropy (FA), a popular diffusion tensor imaging (DTI) metric of WM coherence, in 130 healthy young participants. Loss aversion was positively correlated with FA in bundles that might underpin attentional biases towards negative stimuli (forceps minor), the associated aversive affective states (fornix), and the motivational incentive to avoid them (cingulum). Conversely, a negative correlation was found in bundles previously associated with reward sensitivity through projections to fronto-striatal structures (superior longitudinal fasciculus and inferior fronto-occipital fasciculus), possibly decreasing loss aversion by enhancing the salience of potential gains. The observation of positive and negative correlations with FA in distinct WM bundles supports the view that loss aversion reflects the interplay between oppositely-directed reward- and loss-oriented patterns of brain activity and connectivity. These results strengthen the view that loss aversion represents a stable neuro-cognitive component of one's behavioural attitude in risky decision-making, rather than a transient fearful reaction to choice-related information.