title: Spontaneous low-frequency fluctuations in the BOLD signal in schizophrenic patients: anomalies in the default network.
abstract: Spontaneous low-frequency fluctuations in the blood oxygen level-dependent (BOLD) functional magnetic resonance imaging (MRI) signal have been shown to reflect neural synchrony between brain regions. A "default network" of spontaneous low-frequency fluctuations has been described in healthy volunteers during stimulus-independent thought. Negatively correlated with this network are regions activated during attention-demanding tasks. Both these networks involve brain regions and functions that have been linked with schizophrenia in previous research. The present study examined spontaneous slow fluctuations in the BOLD signal at rest, as measured by correlation with low-frequency oscillations in the posterior cingulate, in 17 schizophrenic patients, and 17 comparable healthy volunteers. Healthy volunteers demonstrated correlation between spontaneous low-frequency fluctuations of the BOLD signal in the posterior cingulate and fluctuations in the lateral parietal, medial prefrontal, and cerebellar regions, similar to previous reports. Schizophrenic patients had significantly less correlation between spontaneous slow activity in the posterior cingulate and that in the lateral parietal, medial prefrontal, and cerebellar regions. Connectivity of the posterior cingulate was found to vary with both positive and negative symptoms in schizophrenic patients. Because these data suggest significant abnormalities in resting-state neural networks in schizophrenia, further investigations of spontaneous slow fluctuations of the BOLD signal seem warranted in this population.
authors.affiliation: Department of Psychiatry, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Canada.
authors.forename: Robyn L
authors.initials: RL
authors.lastname: Bluhm
authors.forename: Jodi
authors.initials: J
authors.lastname: Miller
authors.forename: Ruth A
authors.initials: RA
authors.lastname: Lanius
authors.forename: Elizabeth A
authors.initials: EA
authors.lastname: Osuch
authors.forename: Kristine
authors.initials: K
authors.lastname: Boksman
authors.forename: R W J
authors.initials: RW
authors.lastname: Neufeld
authors.forename: Jean
authors.initials: J
authors.lastname: Théberge
authors.forename: Betsy
authors.initials: B
authors.lastname: Schaefer
authors.forename: Peter
authors.initials: P
authors.lastname: Williamson
mesh_terms: D000328:Adult; D001921:Brain / Q000098:blood supply / Q000503:physiopathology; D002560:Cerebrovascular Circulation / Q000502:physiology; D005260:Female; D007839:Functional Laterality / Q000502:physiology; D006179:Gyrus Cinguli / Q000503:physiopathology; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D009415:Nerve Net / Q000503:physiopathology*; D010100:Oxygen / Q000097:blood; D012559:Schizophrenia / Q000503:physiopathology*; D015398:Signal Transduction / Q000502:physiology*
chemical_list: D010100:Oxygen