title: Reward System Dysfunction as a Neural Substrate of Symptom Expression Across the General Population and Patients With Schizophrenia.
abstract: Dysfunctional patterns of activation in brain reward networks have been suggested as a core element in the pathophysiology of schizophrenia. However, it remains unclear whether this dysfunction is specific to schizophrenia or can be continuously observed across persons with different levels of nonclinical and clinical symptom expression. Therefore, we sought to investigate whether the pattern of reward system dysfunction is consistent with a dimensional or categorical model of psychosis-like symptom expression. 23 patients with schizophrenia and 37 healthy control participants with varying levels of psychosis-like symptoms, separated into 3 groups of low, medium, and high symptom expression underwent event-related functional magnetic resonance imaging while performing a Cued Reinforcement Reaction Time task. We observed lower activation in the ventral striatum during the expectation of high vs no reward to be associated with higher symptom expression across all participants. No significant difference between patients with schizophrenia and healthy participants with high symptom expression was found. However, connectivity between the ventral striatum and the medial orbitofrontal cortex was specifically reduced in patients with schizophrenia. Dysfunctional local activation of the ventral striatum depends less on diagnostic category than on the degree of symptom expression, therefore showing a pattern consistent with a psychosis continuum. In contrast, aberrant connectivity in the reward system is specific to patients with schizophrenia, thereby supporting a categorical view. Thus, the results of the present study provide evidence for both continuous and discontinuous neural substrates of symptom expression across patients with schizophrenia and the general population.
authors.affiliation: Section of Experimental Psychopathology and Neurophysiology, Department of Child and Adolescent Psychiatry, Centre for Psychosocial Medicine, Heidelberg, Germany; Department of General Internal Medicine and Psychosomatics, Centre for Psychosocial Medicine, Heidelberg, Germany; Joe.simon@med.uni-heidelberg.de.
authors.forename: Joe J
authors.initials: JJ
authors.lastname: Simon
authors.affiliation: Department of General Adult Psychiatry, Centre for Psychosocial Medicine, Heidelberg, Germany;
authors.forename: Sheila A
authors.initials: SA
authors.lastname: Cordeiro
authors.affiliation: Department of Diagnostic and Interventional Radiology, University Hospital Heidelberg, Heidelberg, Germany;
authors.forename: Marc-André
authors.initials: MA
authors.lastname: Weber
authors.affiliation: Department of General Internal Medicine and Psychosomatics, Centre for Psychosocial Medicine, Heidelberg, Germany; LVR-Klinikum Essen, Department of Psychosomatic Medicine and Psychotherapy, Essen, Germany;
authors.forename: Hans-Christoph
authors.initials: HC
authors.lastname: Friederich
authors.affiliation: Department of General Adult Psychiatry, Centre for Psychosocial Medicine, Heidelberg, Germany; Department of Psychiatry, Psychotherapy and Psychosomatics, Saarland University, Homburg, Germany;
authors.forename: Robert C
authors.initials: RC
authors.lastname: Wolf
authors.affiliation: Section of Experimental Psychopathology and Neurophysiology, Department of Child and Adolescent Psychiatry, Centre for Psychosocial Medicine, Heidelberg, Germany; Department of General Adult Psychiatry, Centre for Psychosocial Medicine, Heidelberg, Germany; SRH Klinikum, Karlsbad-Langensteinbach, Germany;
authors.forename: Matthias
authors.initials: M
authors.lastname: Weisbrod
authors.affiliation: Department of Psychiatry, Psychotherapy and Psychosomatics, Psychiatric Hospital, University of Zurich, Zurich, Switzerland.
authors.forename: Stefan
authors.initials: S
authors.lastname: Kaiser
mesh_terms: D000328:Adult; D059031:Anticipation, Psychological / Q000502:physiology; D057565:Apathy / Q000502:physiology; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D009415:Nerve Net / Q000503:physiopathology*; D017397:Prefrontal Cortex / Q000503:physiopathology*; D011618:Psychotic Disorders / Q000503:physiopathology*; D012201:Reward; D012559:Schizophrenia / Q000503:physiopathology*; D066328:Ventral Striatum / Q000503:physiopathology*; D055815:Young Adult
keywords: apathy; cued reinforcement reaction time task; dimensional symptom expression; functional magnetic resonance imaging; psychosis-like symptom expression; ventral striatum