Cortical thickness correlates of probabilistic reward learning in young adults.

While impairments in reward learning have been observed in depression, individual differences also exist among healthy normative populations and these differences have been parametrically mapped onto naturally occurring inter-individual variability in neuroanatomy. To date, alterations of cortical thickness as a function of reward learning have not been studied. Structural MRI and behaviourally assessedrobabilistic reward learning data from 103 participants (nmale = 35, nfemale = 68, age = 19.0 ± 1.0 years) from the Duke Neurogenetics Study were used in our analysis. The relationship between reward learning and vertex-wise cortical thickness was tested with a multiple linear regression including gender, age, and reward task stimulus discriminability as nuisance variables. Reward learning was significantly, positively associated with cortical thickness in the right medial superior frontal cortex (t = 4.469, pFWER = .048). This is the first study exploring the relationship between cortical thickness and probabilistic reward learning. It implicates a novel region in reward learning and can thereby inform future mechanistic studies.