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Motivational Deficits in Schizophrenia Examined

Cogn Affect Behav Neurosci; 2018 Dec; Hernaus, et al

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.

Hernaus D, Xu Z, Brown EC, et al. Motivational deficits in schizophrenia relate to abnormalities in cortical learning rate signals. Cogn Affect Behav Neurosci. 2018;18:1338. doi:10.3758/s13415-018-0643-z.