title: Disentangling resting-state BOLD variability and PCC functional connectivity in 22q11.2 deletion syndrome.
abstract: Although often ignored in fMRI studies, moment-to-moment variability of blood oxygenation level dependent (BOLD) signals reveals important information about brain function. Indeed, higher brain signal variability has been associated with better cognitive performance in young adults compared to children and elderly adults. Functional connectivity, a very common approach in resting-state fMRI analysis, is scaled for variance. Thus, alterations might be confounded or driven by BOLD signal variance alterations. Chromosome 22q11.2 deletion syndrome (22q11.2DS) is a neurodevelopmental disorder that is associated with a vast cognitive and clinical phenotype. To date, several resting-state fMRI studies reported altered functional connectivity in 22q11.2DS, however BOLD signal variance has not yet been analyzed. Here, we employed PLS correlation analysis to reveal multivariate patterns of diagnosis-related alterations and age-relationship throughout the cortex of 50 patients between 9 and 25 years old and 50 healthy controls in the same age range. To address how functional connectivity in the default mode network is influenced by BOLD signal fluctuations, we conducted the same analysis on seed-to-voxel connectivity of the posterior cingulate cortex (PCC) and compared resulting brain patterns. BOLD signal variance was lower mainly in regions of the default mode network and in the dorsolateral prefrontal cortex, but higher in large parts of the temporal lobes. In those regions, BOLD signal variance was correlated with age in healthy controls, but not in patients, suggesting deviant developmental trajectories from child- to adulthood. Positive connectivity of the PCC within the default mode network as well as negative connectivity towards the frontoparietal network were weaker in patients with 22q11.2DS. We furthermore showed that lower functional connectivity of the PCC was not driven by higher BOLD signal variability. Our results confirm the strong implication of BOLD variance in aging and give an initial insight in its relationship with functional connectivity in the DMN.
authors.affiliation: Medical Image Processing Laboratory, Institute of Bioengineering, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland; Department of Radiology and Medical Informatics, University of Geneva, Geneva, Switzerland; Developmental Imaging and Psychopathology Laboratory, Office Médico-Pédagogique, Department of Psychiatry, University of Geneva, Geneva, Switzerland. Electronic address: daniela.zoller@epfl.ch.
authors.forename: Daniela
authors.initials: D
authors.lastname: Zöller
authors.affiliation: Developmental Imaging and Psychopathology Laboratory, Office Médico-Pédagogique, Department of Psychiatry, University of Geneva, Geneva, Switzerland.
authors.forename: Marie
authors.initials: M
authors.lastname: Schaer
authors.affiliation: Developmental Imaging and Psychopathology Laboratory, Office Médico-Pédagogique, Department of Psychiatry, University of Geneva, Geneva, Switzerland.
authors.forename: Elisa
authors.initials: E
authors.lastname: Scariati
authors.affiliation: Developmental Imaging and Psychopathology Laboratory, Office Médico-Pédagogique, Department of Psychiatry, University of Geneva, Geneva, Switzerland.
authors.forename: Maria Carmela
authors.initials: MC
authors.lastname: Padula
authors.affiliation: Developmental Imaging and Psychopathology Laboratory, Office Médico-Pédagogique, Department of Psychiatry, University of Geneva, Geneva, Switzerland.
authors.forename: Stephan
authors.initials: S
authors.lastname: Eliez
authors.affiliation: Medical Image Processing Laboratory, Institute of Bioengineering, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland; Department of Radiology and Medical Informatics, University of Geneva, Geneva, Switzerland.
authors.forename: Dimitri
authors.initials: D
authors.lastname: Van De Ville
mesh_terms: D000293:Adolescent; D000328:Adult; D001921:Brain / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D001931:Brain Mapping / Q000379:methods*; D002648:Child; D004062:DiGeorge Syndrome / Q000503:physiopathology*; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods; D008279:Magnetic Resonance Imaging; D008297:Male; D009434:Neural Pathways / Q000503:physiopathology*; D055815:Young Adult
keywords: 22q11.2 deletion syndrome; BOLD signal variability; Default mode network; Functional connectivity; Resting-state fMRI