Recent findings point to an impairment in learning rate modulation in people with schizophrenia (PSZ), leading to a reduced ability to adjust task behavior in response to unexpected outcomes. Learning rate modulation deficits may be associated with decreased involvement of the dorsomedial prefrontal cortex (dmPFC) within a greater reinforcement learning network. 26 PSZ and 23 healthy volunteers completed a probabilistic reinforcement learning paradigm with occasional, sudden, shifts in contingencies. Researchers found:

• Using computational modeling, evidence was found of an impairment in trial-wise learning rate modulation (α) in PSZ before and after a reinforcement contingency shift, expressed most in PSZ with more severe motivational deficits.
• In a subsample of 22 PSZ and 22 healthy volunteers, there was little evidence for between-group differences in ventral striatum reward prediction error (VS RPE) signals and dmPFC learning rate signals, as measured with functional magnetic resonance imaging.
• However, a follow-up psychophysiological interaction analysis revealed decreased dmPFC-VS connectivity concurrent with learning rate modulation, most prominently in individuals with the most severe motivational deficits.