title: Spontaneous default network activity reflects behavioral variability independent of mind-wandering.
abstract: The brain's default mode network (DMN) is highly active during wakeful rest when people are not overtly engaged with a sensory stimulus or externally oriented task. In multiple contexts, increased spontaneous DMN activity has been associated with self-reported episodes of mind-wandering, or thoughts that are unrelated to the present sensory environment. Mind-wandering characterizes much of waking life and is often associated with error-prone, variable behavior. However, increased spontaneous DMN activity has also been reliably associated with stable, rather than variable, behavior. We aimed to address this seeming contradiction and to test the hypothesis that single measures of attentional states, either based on self-report or on behavior, are alone insufficient to account for DMN activity fluctuations. Thus, we simultaneously measured varying levels of self-reported mind-wandering, behavioral variability, and brain activity with fMRI during a unique continuous performance task optimized for detecting attentional fluctuations. We found that even though mind-wandering co-occurred with increased behavioral variability, highest DMN signal levels were best explained by intense mind-wandering combined with stable behavior simultaneously, compared with considering either single factor alone. These brain-behavior-experience relationships were highly consistent within known DMN subsystems and across DMN subregions. In contrast, such relationships were absent or in the opposite direction for other attention-relevant networks (salience, dorsal attention, and frontoparietal control networks). Our results suggest that the cognitive processes that spontaneous DMN activity specifically reflects are only partially related to mind-wandering and include also attentional state fluctuations that are not captured by self-report.
authors.affiliation: Department of Neurology & Neurological Sciences, Stanford University, Stanford, CA 94305.|Department of Psychiatry, Harvard Medical School, Boston, MA 02129.|Department of Psychiatry, Massachusetts General Hospital, Charlestown, MA 02129.
authors.forename: Aaron
authors.initials: A
authors.lastname: Kucyi
authors.affiliation: Boston Attention and Learning Laboratory, Veterans Administration, Boston Healthcare System, Boston, MA 02130.|Neuroimaging Research for Veterans Center (NeRVe), Veterans Administration, Boston Healthcare System, Boston, MA 02130.|Department of Psychiatry, Boston University School of Medicine, Boston, MA 02130.
authors.forename: Michael
authors.initials: M
authors.lastname: Esterman
authors.affiliation: Department of Psychiatry, Massachusetts General Hospital, Charlestown, MA 02129.
authors.forename: Clay S
authors.initials: CS
authors.lastname: Riley
authors.affiliation: Department of Psychiatry, Harvard Medical School, Boston, MA 02129; eve_valera@hms.harvard.edu.|Department of Psychiatry, Massachusetts General Hospital, Charlestown, MA 02129.
authors.forename: Eve M
authors.initials: EM
authors.lastname: Valera
mesh_terms: D000328:Adult; D001288:Attention / Q000502:physiology*; D001921:Brain / Q000502:physiology*; D001931:Brain Mapping; D005201:Fantasy; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D009415:Nerve Net / Q000502:physiology*; D012146:Rest / Q000502:physiology*; D014796:Visual Perception / Q000502:physiology
keywords: daydreaming; default mode network; resting state; spontaneous thought; sustained attention