TY - JOUR
T1 - Hippocampal atrophy and intrinsic brain network dysfunction relate to alterations in mind wandering in neurodegeneration
AU - O’Callaghan, Claire
AU - Shine, James M.
AU - Hodges, John R.
AU - Andrews-Hanna, Jessica R.
AU - Irish, Muireann
N1 - Funding Information:
We thank Nadene Dermody and Jody Kamminga for assistance with data collection and scoring. C.O. was supported by a National Health and Medical Research Council (NHMRC) Neil Hamilton Fairley Fellowship Grant GNT1091310 and by the Wellcome Trust (Grant 200181/Z/15/Z). J.M.S. was supported by a NHMRC CJ Martin Fellowship Grant GNT1072403. J.R.A.-H. was supported by the University of Arizona and a grant from the John Templeton Foundation, “Prospective Psychology Stage 2: A Research Competition” to Martin Seligman. M.I. was supported by an Australian Research Council (ARC) Future Fellowship (Grant FT160100096) and an ARC Discovery Project (Grant DP180101548). This work was supported by funding to ForeFront, a collaborative research group dedicated to the study of frontotemporal dementia and motor neuron disease, from the NHMRC (Grant APP1037746) and the ARC Centre of Excellence in Cognition and its Disorders (Grant CE11000102). The opinions expressed in this paper are those of the author(s) and do not necessarily reflect the views of the John Templeton Foundation.
Publisher Copyright:
© 2019 National Academy of Sciences. All Rights Reserved.
PY - 2019/2/19
Y1 - 2019/2/19
N2 - Mind wandering represents the human capacity for internally focused thought and relies upon the brain’s default network and its interactions with attentional networks. Studies have characterized mind wandering in healthy people, yet there is limited understanding of how this capacity is affected in clinical populations. This paper used a validated thought-sampling task to probe mind wandering capacity in two neurodegenerative disorders: behavioral variant frontotemporal dementia [(bvFTD); n = 35] and Alzheimer’s disease [(AD); n = 24], compared with older controls (n = 37). These patient groups were selected due to canonical structural and functional changes across sites of the default and frontoparietal networks and well-defined impairments in cognitive processes that support mind wandering. Relative to the controls, bvFTD patients displayed significantly reduced mind wandering capacity, offset by a significant increase in stimulus-bound thought. In contrast, AD patients demonstrated comparable levels of mind wandering to controls, in the context of a relatively subtle shift toward stimulus-/task-related forms of thought. In the patient groups, mind wandering was associated with gray matter integrity in the hippocampus/parahippocampus, striatum, insula, and orbitofrontal cortex. Resting-state functional connectivity revealed associations between mind wandering capacity and connectivity within and between regions of the frontoparietal and default networks with distinct patterns evident in patients vs. controls. These findings support a relationship between altered mind wandering capacity in neurodegenerative disorders and structural and functional integrity of the default and frontoparietal networks. This paper highlights a dimension of cognitive dysfunction not well documented in neurodegenerative disorders and validates current models of mind wandering in a clinical population.
AB - Mind wandering represents the human capacity for internally focused thought and relies upon the brain’s default network and its interactions with attentional networks. Studies have characterized mind wandering in healthy people, yet there is limited understanding of how this capacity is affected in clinical populations. This paper used a validated thought-sampling task to probe mind wandering capacity in two neurodegenerative disorders: behavioral variant frontotemporal dementia [(bvFTD); n = 35] and Alzheimer’s disease [(AD); n = 24], compared with older controls (n = 37). These patient groups were selected due to canonical structural and functional changes across sites of the default and frontoparietal networks and well-defined impairments in cognitive processes that support mind wandering. Relative to the controls, bvFTD patients displayed significantly reduced mind wandering capacity, offset by a significant increase in stimulus-bound thought. In contrast, AD patients demonstrated comparable levels of mind wandering to controls, in the context of a relatively subtle shift toward stimulus-/task-related forms of thought. In the patient groups, mind wandering was associated with gray matter integrity in the hippocampus/parahippocampus, striatum, insula, and orbitofrontal cortex. Resting-state functional connectivity revealed associations between mind wandering capacity and connectivity within and between regions of the frontoparietal and default networks with distinct patterns evident in patients vs. controls. These findings support a relationship between altered mind wandering capacity in neurodegenerative disorders and structural and functional integrity of the default and frontoparietal networks. This paper highlights a dimension of cognitive dysfunction not well documented in neurodegenerative disorders and validates current models of mind wandering in a clinical population.
KW - Alzheimer’s disease
KW - Behavioral
KW - Default mode network
KW - Hippocampus
KW - Mind wandering
KW - Variant frontotemporal dementia
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U2 - 10.1073/pnas.1818523116
DO - 10.1073/pnas.1818523116
M3 - Article
C2 - 30718430
AN - SCOPUS:85061844147
VL - 116
SP - 3316
EP - 3321
JO - Proceedings of the National Academy of Sciences of the United States of America
JF - Proceedings of the National Academy of Sciences of the United States of America
SN - 0027-8424
IS - 8
ER -