title: Brain Dynamics of Aging: Multiscale Variability of EEG Signals at Rest and during an Auditory Oddball Task
abstract: The present work focused on the study of fluctuations of cortical activity across time scales in young and older healthy adults. The main objective was to offer a comprehensive characterization of the changes of brain (cortical) signal variability during aging, and to make the link with known underlying structural, neurophysiological, and functional modifications, as well as aging theories. We analyzed electroencephalogram (EEG) data of young and elderly adults, which were collected at resting state and during an auditory oddball task. We used a wide battery of metrics that typically are separately applied in the literature, and we compared them with more specific ones that address their limits. Our procedure aimed to overcome some of the methodological limitations of earlier studies and verify whether previous findings can be reproduced and extended to different experimental conditions. In both rest and task conditions, our results mainly revealed that EEG signals presented systematic age-related changes that were time-scale-dependent with regard to the structure of fluctuations (complexity) but not with regard to their magnitude. Namely, compared with young adults, the cortical fluctuations of the elderly were more complex at shorter time scales, but less complex at longer scales, although always showing a lower variance. Additionally, the elderly showed signs of spatial, as well as between, experimental conditions dedifferentiation. By integrating these so far isolated findings across time scales, metrics, and conditions, the present study offers an overview of age-related changes in the fluctuation electrocortical activity while making the link with underlying brain dynamics.
authors.affiliation: Aix-Marseille Université, Inserm, Institut de Neurosciences des Systèmes UMR_S 1106 , 13385, Marseille, France ; Aix-Marseille Université, CNRS, Institut des Sciences du Mouvement UMR 7287 , 13288, Marseille, France.
authors.forename: Rita
authors.initials: R
authors.lastname: Sleimen-Malkoun
authors.affiliation: Aix-Marseille Université, Inserm, Institut de Neurosciences des Systèmes UMR_S 1106 , 13385, Marseille, France ; Max Planck Institute for Human Development, Center for Lifespan Psychology , 14195, Berlin, Germany.
authors.forename: Dionysios
authors.initials: D
authors.lastname: Perdikis
authors.affiliation: Max Planck Institute for Human Development, Center for Lifespan Psychology , 14195, Berlin, Germany.
authors.forename: Viktor
authors.initials: V
authors.lastname: Müller
authors.affiliation: Aix-Marseille Université, Inserm, Institut de Neurosciences des Systèmes UMR_S 1106 , 13385, Marseille, France ; CNRS , 13402, Marseille, France.
authors.forename: Jean-Luc
authors.initials: JL
authors.lastname: Blanc
authors.affiliation: Aix-Marseille Université, Inserm, Institut de Neurosciences des Systèmes UMR_S 1106 , 13385, Marseille, France ; CNRS , 13402, Marseille, France.
authors.forename: Raoul
authors.initials: R
authors.lastname: Huys
authors.affiliation: Aix-Marseille Université, CNRS, Institut des Sciences du Mouvement UMR 7287 , 13288, Marseille, France.
authors.forename: Jean-Jacques
authors.initials: JJ
authors.lastname: Temprado
authors.affiliation: Aix-Marseille Université, Inserm, Institut de Neurosciences des Systèmes UMR_S 1106 , 13385, Marseille, France ; CNRS , 13402, Marseille, France.
authors.forename: Viktor K
authors.initials: VK
authors.lastname: Jirsa
keywords: EEG; aging; brain dynamics; brain signal variability; complexity; multiscale entropy