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Abnormal dorsal attention network activation in memory impairment after traumatic brain injury

Title: Abnormal dorsal attention network activation in memory impairment after traumatic brain injury
Authors: Mallas, E-J
De Simoni, S
Scott, G
Jolly, A
Hampshire, A
Li, L
Bourke, N
Roberts, S
Gorgoraptis, N
Sharp, D
Item Type: Journal Article
Abstract: Memory impairment is a common, disabling effect of traumatic brain injury. In healthy individuals, successful memory encoding is associated with activation of the dorsal attention network as well as suppression of the default mode network. Here, in traumatic brain injurypatients we examined whether: i) impairments in memory encoding are associated with abnormal brain activation in these networks; ii) whether changes in this brain activity predict subsequent memory retrieval; and iii) whether abnormal white matter integrity underpinningfunctional networks is associated with impaired subsequent memory. 35 patients with moderate-severetraumatic brain injury aged 23-65 years (74% males) in the post-acute/chronic phase after injury and 16 healthy controls underwent functional MRI during performance of an abstract image memory encoding task. Diffusion tensor imaging was used to assess structural abnormalities across patient groups compared to 28 age-matched healthy controls. Successful memory encoding across all participants was associated with activation of the dorsal attention network, the ventral visual stream and medial temporal lobes. Decreased activation was seen in the default mode network. Patients with preserved episodic memory demonstrated increased activation in areas of the dorsal attention network.Patients with impaired memory showed increased left anterior prefrontal activity. White matter microstructure underpinning connectivity between core nodes of the encoding networks was significantly reduced in patients with memory impairment. Our results show for the first time that patients with impaired episodic memory show abnormal activation of key nodes within the dorsal attention network and regions regulating default mode network activity during encoding. Successful encoding was associated with an opposite direction of signal change between patients with and without memory impairment, suggesting that memory encoding mechanisms could be fundamentally altered in this population. We demonstrate a clear relationship between functional networks activated during encoding and underlying abnormalities within the structural connectome in patients with memory impairment. We suggest that encoding failures in this group are likely due to failed control of goal-directed attentional resources.
Issue Date: Jan-2021
Date of Acceptance: 19-Aug-2020
URI: http://hdl.handle.net/10044/1/83390
DOI: 10.1093/brain/awaa380
ISSN: 0006-8950
Publisher: Oxford University Press (OUP)
Start Page: 114
End Page: 127
Journal / Book Title: Brain: a journal of neurology
Volume: 144
Issue: 1
Copyright Statement: © The Author(s) (2020). Published by Oxford University Press on behalf of the Guarantors of Brain. All rights reserved. For permissions, please email: journals.permissions@oup.com This article is published and distributed under the terms of the Oxford University Press, Standard Journals Publication Model (https://academic.oup.com/journals/pages/open_access/funder_policies/chorus/standard_publication_model). This is a pre-copy-editing, author-produced version of an article accepted for publication in Brain following peer review. The definitive publisher-authenticated version Emma-Jane Mallas, Sara De Simoni, Gregory Scott, Amy E Jolly, Adam Hampshire, Lucia M Li, Niall J Bourke, Stuart A G Roberts, Nikos Gorgoraptis, David J Sharp, Abnormal dorsal attention network activation in memory impairment after traumatic brain injury, Brain, Volume 144, Issue 1, January 2021, Pages 114–127 is available online at: https://doi.org/10.1093/brain/awaa380
Sponsor/Funder: Imperial College Healthcare NHS Trust- BRC Funding
Imperial College Healthcare NHS Trust- BRC Funding
Medical Research Council (MRC)
Imperial College Healthcare NHS Trust- BRC Funding
Imperial College Healthcare NHS Trust- BRC Funding
Imperial Health Charity
The Royal British Legion
National Institute for Health Research
National Institute for Health Research
UK DRI Ltd
Wellcome Trust
Funder's Grant Number: RDA03
RDC04 79560
MR/L022141/1
RDA03_79560
RDC04
RF16\100016
Centre for Blast Injury Studie
NIHR-RP-011-048
RDLRN (RCF - 27)
'CR & T IMP'
103429/Z/13/Z
Keywords: TBI
goal-directed behaviour
imaging
memory
Neurology & Neurosurgery
11 Medical and Health Sciences
17 Psychology and Cognitive Sciences
Publication Status: Published
Online Publication Date: 2020-12-26
Appears in Collections:Faculty of Medicine
Department of Brain Sciences