title: Altered resting-state EEG source functional connectivity in schizophrenia: the effect of illness duration.
abstract: Despite the increasing body of evidence supporting the hypothesis of schizophrenia as a disconnection syndrome, studies of resting-state EEG Source Functional Connectivity (EEG-SFC) in people affected by schizophrenia are sparse. The aim of the present study was to investigate resting-state EEG-SFC in 77 stable, medicated patients with schizophrenia (SCZ) compared to 78 healthy volunteers (HV). In order to study the effect of illness duration, SCZ were divided in those with a short duration of disease (SDD; n = 25) and those with a long duration of disease (LDD; n = 52). Resting-state EEG recordings in eyes closed condition were analyzed and lagged phase synchronization (LPS) indices were calculated for each ROI pair in the source-space EEG data. In delta and theta bands, SCZ had greater EEG-SFC than HV; a higher theta band connectivity in frontal regions was observed in LDD compared with SDD. In the alpha band, SCZ showed lower frontal EEG-SFC compared with HV whereas no differences were found between LDD and SDD. In the beta1 band, SCZ had greater EEG-SFC compared with HVs and in the beta2 band, LDD presented lower frontal and parieto-temporal EEG-SFC compared with HV. In the gamma band, SDD had greater connectivity values compared with LDD and HV. This study suggests that resting state brain network connectivity is abnormally organized in schizophrenia, with different patterns for the different EEG frequency components and that EEG can be a powerful tool to further elucidate the complexity of such disordered connectivity.
authors.affiliation: Laboratory of Psychophysiology, Chair of Psychiatry, Department of Systems Medicine, University of Rome "Tor Vergata" Rome, Italy ; Chair of Psychiatry, Department of Systems Medicine, University of Rome "Tor Vergata" Rome, Italy.
authors.forename: Giorgio
authors.initials: G
authors.lastname: Di Lorenzo
authors.affiliation: Laboratory of Psychophysiology, Chair of Psychiatry, Department of Systems Medicine, University of Rome "Tor Vergata" Rome, Italy ; Chair of Psychiatry, Department of Systems Medicine, University of Rome "Tor Vergata" Rome, Italy ; Psychiatric Clinic, Fondazione Policlinico "Tor Vergata" Rome, Italy.
authors.forename: Andrea
authors.initials: A
authors.lastname: Daverio
authors.affiliation: Chair of Psychiatry, Department of Systems Medicine, University of Rome "Tor Vergata" Rome, Italy ; Psychiatric Clinic, Fondazione Policlinico "Tor Vergata" Rome, Italy.
authors.forename: Fabiola
authors.initials: F
authors.lastname: Ferrentino
authors.affiliation: Department of Medicine, Surgery and Neuroscience, University of Siena Siena, Italy ; Berenson-Allen Center for Non-Invasive Brain Stimulation, Beth Israel Medical Center, Harvard Medical School Boston, MA, USA.
authors.forename: Emiliano
authors.initials: E
authors.lastname: Santarnecchi
authors.affiliation: Laboratory of Psychophysiology, Chair of Psychiatry, Department of Systems Medicine, University of Rome "Tor Vergata" Rome, Italy ; Chair of Psychiatry, Department of Systems Medicine, University of Rome "Tor Vergata" Rome, Italy ; Psychiatric Clinic, Fondazione Policlinico "Tor Vergata" Rome, Italy.
authors.forename: Fabio
authors.initials: F
authors.lastname: Ciabattini
authors.affiliation: Laboratory of Psychophysiology, Chair of Psychiatry, Department of Systems Medicine, University of Rome "Tor Vergata" Rome, Italy ; Chair of Psychiatry, Department of Systems Medicine, University of Rome "Tor Vergata" Rome, Italy.
authors.forename: Leonardo
authors.initials: L
authors.lastname: Monaco
authors.affiliation: Chair of Psychiatry, Department of Systems Medicine, University of Rome "Tor Vergata" Rome, Italy ; Psychiatric Clinic, Fondazione Policlinico "Tor Vergata" Rome, Italy.
authors.forename: Giulia
authors.initials: G
authors.lastname: Lisi
authors.affiliation: Chair of Psychiatry, Department of Systems Medicine, University of Rome "Tor Vergata" Rome, Italy ; Psychiatric Clinic, Fondazione Policlinico "Tor Vergata" Rome, Italy.
authors.forename: Ylenia
authors.initials: Y
authors.lastname: Barone
authors.affiliation: Don Carlo Gnocchi Onlus Foundation Milano, Italy.
authors.forename: Cherubino
authors.initials: C
authors.lastname: Di Lorenzo
authors.affiliation: Chair of Psychiatry, Department of Systems Medicine, University of Rome "Tor Vergata" Rome, Italy ; Psychiatric Clinic, Fondazione Policlinico "Tor Vergata" Rome, Italy.
authors.forename: Cinzia
authors.initials: C
authors.lastname: Niolu
authors.affiliation: School of Life and Health Sciences, Aston Brain Centre, Aston University Birmingham, UK.
authors.forename: Stefano
authors.initials: S
authors.lastname: Seri
authors.affiliation: Laboratory of Psychophysiology, Chair of Psychiatry, Department of Systems Medicine, University of Rome "Tor Vergata" Rome, Italy ; Chair of Psychiatry, Department of Systems Medicine, University of Rome "Tor Vergata" Rome, Italy ; Psychiatric Clinic, Fondazione Policlinico "Tor Vergata" Rome, Italy.
authors.forename: Alberto
authors.initials: A
authors.lastname: Siracusano
keywords: brain network; brain oscillations; disconnectivity; excitatory/inhibitory dysfunction; neural plasticity; psychosis; schizophrenia; synchronization