title: Independent component model of the default-mode brain function: combining individual-level and population-level analyses in resting-state fMRI.
abstract: Resting-state functional magnetic resonance imaging (RS-fMRI) is a technique used to investigate the spontaneous correlations of blood-oxygen-level-dependent signals across different regions of the brain. Using functional connectivity tools, it is possible to investigate a specific RS-fMRI network, referred to as "default-mode" (DM) network, that involves cortical regions deactivated in fMRI experiments with cognitive tasks. Previous works have reported a significant effect of aging on DM regions activity. Independent component analysis (ICA) is often used for generating spatially distributed DM functional connectivity patterns from RS-fMRI data without the need for a reference region. This aspect and the relatively easy setup of an RS-fMRI experiment even in clinical trials have boosted the combined use of RS-fMRI and ICA-based DM analysis for noninvasive research of brain disorders. In this work, we considered different strategies for combining ICA results from individual-level and population-level analyses and used them to evaluate and predict the effect of aging on the DM component. Using RS-fMRI data from 20 normal subjects and a previously developed group-level ICA methodology, we generated group DM maps and showed that the overall ICA-DM connectivity is negatively correlated with age. A negative correlation of the ICA voxel weights with age existed in all DM regions at a variable degree. As an alternative approach, we generated a distributed DM spatial template and evaluated the correlation of each individual DM component fit to this template with age. Using a "leave-one-out" procedure, we discuss the importance of removing the bias from the DM template-generation process.
authors.affiliation: Department of Neuroscience, University of Naples Federico II, Naples, Italy. fabrizio.esposito@unina.it
authors.forename: Fabrizio
authors.initials: F
authors.lastname: Esposito
authors.forename: Adriana
authors.initials: A
authors.lastname: Aragri
authors.forename: Ilaria
authors.initials: I
authors.lastname: Pesaresi
authors.forename: Sossio
authors.initials: S
authors.lastname: Cirillo
authors.forename: Gioacchino
authors.initials: G
authors.lastname: Tedeschi
authors.forename: Elio
authors.initials: E
authors.lastname: Marciano
authors.forename: Rainer
authors.initials: R
authors.lastname: Goebel
authors.forename: Francesco
authors.initials: F
authors.lastname: Di Salle
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D001921:Brain / Q000098:blood supply / Q000502:physiology*; D001931:Brain Mapping / Q000379:methods*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008875:Middle Aged; D010100:Oxygen / Q000097:blood
chemical_list: D010100:Oxygen