title: Age differences in the default network at rest and the relation to self-referential processing.
abstract: Older adults show a 'positivity bias' in tasks involving emotion and self-referential processing. A critical network that is involved in self-referencing and shows age-related decline is the default network (DN). The purpose of the current study was to investigate age differences in pre- and post-task DN functional connectivity (FC) and signal variability, and to examine whether they are predictive of the positivity bias in self-referencing. We measured FC and within-subject variability of the DN in resting-state scans preceding and following tasks involving personality judgements on the self and a close other. Older adults endorsed more positive traits than younger adults on both tasks. FC was weaker post-task in older vs younger adults, and younger adults had greater variability than older adults in DN nodes. Younger adults with higher post-task DN variability had more negative self-ratings. For both age groups, greater FC in the DN was associated with more negative self-ratings. Neither FC nor variability was related to other ratings, despite the potential for self-processing when making other judgements. Our findings suggest that ageing leads to reduced FC and variability in the DN, which is most apparent after task, and may be one mechanism underlying the positive bias with age.
authors.affiliation: Rotman Research Institute at Baycrest, Department of Psychology, University of Toronto, Department of Medical Biophysics, University of Toronto, and Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada Rotman Research Institute at Baycrest, Department of Psychology, University of Toronto, Department of Medical Biophysics, University of Toronto, and Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada c.saverino@mail.utoronto.ca cgrady@research.baycrest.org.
authors.forename: Cristina
authors.initials: C
authors.lastname: Saverino
authors.affiliation: Rotman Research Institute at Baycrest, Department of Psychology, University of Toronto, Department of Medical Biophysics, University of Toronto, and Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Omer
authors.initials: O
authors.lastname: Grigg
authors.affiliation: Rotman Research Institute at Baycrest, Department of Psychology, University of Toronto, Department of Medical Biophysics, University of Toronto, and Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada Rotman Research Institute at Baycrest, Department of Psychology, University of Toronto, Department of Medical Biophysics, University of Toronto, and Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Nathan W
authors.initials: NW
authors.lastname: Churchill
authors.affiliation: Rotman Research Institute at Baycrest, Department of Psychology, University of Toronto, Department of Medical Biophysics, University of Toronto, and Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada Rotman Research Institute at Baycrest, Department of Psychology, University of Toronto, Department of Medical Biophysics, University of Toronto, and Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada Rotman Research Institute at Baycrest, Department of Psychology, University of Toronto, Department of Medical Biophysics, University of Toronto, and Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Cheryl L
authors.initials: CL
authors.lastname: Grady
mesh_terms: D000328:Adult; D000368:Aged; D000375:Aging / Q000502:physiology*; D001931:Brain Mapping; D004644:Emotions / Q000502:physiology; D005260:Female; D006179:Gyrus Cinguli / Q000502:physiology; D006801:Humans; D008297:Male; D009415:Nerve Net / Q000502:physiology*; D010551:Personality / Q000502:physiology; D017397:Prefrontal Cortex / Q000502:physiology; D012146:Rest / Q000502:physiology*; D012649:Self Concept; D055815:Young Adult
keywords: ageing; default network; positivity effect; resting state; self-referential processing