title: Network dynamics during the different stages of hallucinations in schizophrenia.
abstract: The majority of patients with schizophrenia suffer from hallucinations. While the triple-network model, which includes the default mode network (DMN), the central executive network (CEN) and the salience network (SAL), has recently been applied to schizophrenia, how this framework could explain the emergence of hallucinations remains unclear. Therefore, complementary brain regions that have been linked to hallucinations, such as the left hippocampus, should also be considered and added to this model. Accordingly, the present study explored the effective connectivity across these four components (i.e., the quadripartite model) during the different stages of hallucinations. Twenty-five patients with schizophrenia participated in a single session of resting-state functional magnetic resonance imaging to capture hallucinatory experiences. Based on the participants' self-report of the psychosensory experiences that occurred during scanning, hallucinatory experiences were identified and divided into four stages: periods without hallucination ("OFF"), periods with hallucination ("ON"), transition periods between "OFF" and "ON", and the extinction of the hallucinatory experience ("END"). Using stochastic dynamic causal modeling analysis, this study first confirmed that the SAL played a critical and causal role in switching between the CEN and the DMN in schizophrenia. In addition, effective connectivity within the quadripartite model depended on the hallucinatory stage. In particular, "ON" periods were linked to memory-based sensory input from the hippocampus to the SAL, while "END" periods were associated with a takeover of the CEN in favor of a voluntary process. Finally, the pathophysiological and therapeutic implications of these findings are critically discussed. Hum Brain Mapp 37:2571-2586, 2016. © 2016 Wiley Periodicals, Inc.
authors.affiliation: Univ Lille, CNRS UMR-9193, Cognitive and Affective Sciences Laboratory (SCALab), psyCHIC team, F-59000, Lille, France.|CHRU de Lille, Psychiatry Dept, Fontan Hospital, CURE Unit, F-59037, Lille, France.
authors.forename: Stéphanie
authors.initials: S
authors.lastname: Lefebvre
authors.affiliation: Univ Lille, CNRS UMR-9193, Cognitive and Affective Sciences Laboratory (SCALab), psyCHIC team, F-59000, Lille, France.|CHRU de Lille, Psychiatry Dept, Fontan Hospital, CURE Unit, F-59037, Lille, France.|ORPEA-CLINEA group, Lautréamont Clinic, F-59120, Loos, France.
authors.forename: Morgane
authors.initials: M
authors.lastname: Demeulemeester
authors.affiliation: Univ Lille, CNRS UMR-9193, Cognitive and Affective Sciences Laboratory (SCALab), psyCHIC team, F-59000, Lille, France.|CHRU de Lille, Psychiatry Dept, Fontan Hospital, CURE Unit, F-59037, Lille, France.
authors.forename: Arnaud
authors.initials: A
authors.lastname: Leroy
authors.affiliation: CHRU de Lille, Neuroradiology Dpt, Salengro Hospital, F-59037, eLille, France.
authors.forename: Christine
authors.initials: C
authors.lastname: Delmaire
authors.affiliation: Univ Lille, INSERM U1171, Clinical Imaging Core facility (CI2C), F-59000, Lille, France.
authors.forename: Renaud
authors.initials: R
authors.lastname: Lopes
authors.affiliation: Univ Lille, CNRS UMR-9193, Cognitive and Affective Sciences Laboratory (SCALab), psyCHIC team, F-59000, Lille, France.|CHRU de Lille, Psychiatry Dept, Fontan Hospital, CURE Unit, F-59037, Lille, France.
authors.forename: Delphine
authors.initials: D
authors.lastname: Pins
authors.affiliation: Univ Lille, CNRS UMR-9193, Cognitive and Affective Sciences Laboratory (SCALab), psyCHIC team, F-59000, Lille, France.|CHRU de Lille, Psychiatry Dept, Fontan Hospital, CURE Unit, F-59037, Lille, France.
authors.forename: Pierre
authors.initials: P
authors.lastname: Thomas
authors.affiliation: Univ Lille, CNRS UMR-9193, Cognitive and Affective Sciences Laboratory (SCALab), psyCHIC team, F-59000, Lille, France.|CHRU de Lille, Psychiatry Dept, Fontan Hospital, CURE Unit, F-59037, Lille, France.
authors.forename: Renaud
authors.initials: R
authors.lastname: Jardri
mesh_terms: D000328:Adult; D001499:Bayes Theorem; D001921:Brain / Q000000981:diagnostic imaging / Q000503:physiopathology*; D001931:Brain Mapping; D005260:Female; D006212:Hallucinations / Q000000981:diagnostic imaging / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008959:Models, Neurological; D009434:Neural Pathways / Q000000981:diagnostic imaging / Q000503:physiopathology; D011569:Psychiatric Status Rating Scales; D012146:Rest; D012559:Schizophrenia / Q000000981:diagnostic imaging / Q000503:physiopathology*; D057566:Self Report
keywords: brain imaging; dynamic causal modeling; effective connectivity; hallucinations; intrinsic connectivity networks; schizophrenia