title: Antipsychotic dose modulates behavioral and neural responses to feedback during reinforcement learning in schizophrenia.
abstract: Schizophrenia is characterized by an abnormal dopamine system, and dopamine blockade is the primary mechanism of antipsychotic treatment. Consistent with the known role of dopamine in reward processing, prior research has demonstrated that patients with schizophrenia exhibit impairments in reward-based learning. However, it remains unknown how treatment with antipsychotic medication impacts the behavioral and neural signatures of reinforcement learning in schizophrenia. The goal of this study was to examine whether antipsychotic medication modulates behavioral and neural responses to prediction error coding during reinforcement learning. Patients with schizophrenia completed a reinforcement learning task while undergoing functional magnetic resonance imaging. The task consisted of two separate conditions in which participants accumulated monetary gain or avoided monetary loss. Behavioral results indicated that antipsychotic medication dose was associated with altered behavioral approaches to learning, such that patients taking higher doses of medication showed increased sensitivity to negative reinforcement. Higher doses of antipsychotic medication were also associated with higher learning rates (LRs), suggesting that medication enhanced sensitivity to trial-by-trial feedback. Neuroimaging data demonstrated that antipsychotic dose was related to differences in neural signatures of feedback prediction error during the loss condition. Specifically, patients taking higher doses of medication showed attenuated prediction error responses in the striatum and the medial prefrontal cortex. These findings indicate that antipsychotic medication treatment may influence motivational processes in patients with schizophrenia.
authors.affiliation: Department of Psychology, Harvard University, 52 Oxford Street, Cambridge, MA, 02138, USA, insel@fas.harvard.edu.
authors.forename: Catherine
authors.initials: C
authors.lastname: Insel
authors.forename: Jenna
authors.initials: J
authors.lastname: Reinen
authors.forename: Jochen
authors.initials: J
authors.lastname: Weber
authors.forename: Tor D
authors.initials: TD
authors.lastname: Wager
authors.forename: L Fredrik
authors.initials: LF
authors.lastname: Jarskog
authors.forename: Daphna
authors.initials: D
authors.lastname: Shohamy
authors.forename: Edward E
authors.initials: EE
authors.lastname: Smith
mesh_terms: D000328:Adult; D014150:Antipsychotic Agents / Q000008:administration & dosage*; D001921:Brain / Q000187:drug effects* / Q000503:physiopathology; D001931:Brain Mapping; D004305:Dose-Response Relationship, Drug; D030141:Feedback, Psychological / Q000187:drug effects* / Q000502:physiology; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D009042:Motivation / Q000187:drug effects / Q000502:physiology; D009483:Neuropsychological Tests; D011569:Psychiatric Status Rating Scales; D012054:Reinforcement, Psychology; D012201:Reward; D012559:Schizophrenia / Q000188:drug therapy* / Q000503:physiopathology; D012565:Schizophrenic Psychology; D013647:Task Performance and Analysis
chemical_list: D014150:Antipsychotic Agents