Task-evoked metabolic demands of the posteromedial default mode network are shaped by dorsal attention and frontoparietal control networks
- Medical University of Vienna, Austria
- University of Vienna, Austria
- Umeå University, Sweden
- QIMR Berghofer Medical Research Institute, Australia
- University of Newcastle Australia, Australia
Abstract
External tasks evoke characteristic fMRI BOLD signal deactivations in the default mode network (DMN). However, for the corresponding metabolic glucose demands both decreases and increases have been reported. To resolve this discrepancy, functional PET/MRI data from 50 healthy subjects performing Tetris® were combined with previously published data sets of working memory, visual and motor stimulation. We show that the glucose metabolism of the posteromedial DMN is dependent on the metabolic demands of the correspondingly engaged task-positive networks. Specifically, the dorsal attention and frontoparietal network shape the glucose metabolism of the posteromedial DMN in opposing directions. While tasks that mainly require an external focus of attention lead to a consistent downregulation of both metabolism and the BOLD signal in the posteromedial DMN, cognitive control during working memory requires a metabolically expensive BOLD suppression. This indicates that two types of BOLD deactivations with different-oxygen-to-glucose index may occur in this region. We further speculate that consistent downregulation of the two signals is mediated by decreased glutamate signaling, while divergence may be subject to active GABAergic inhibition. The results demonstrate that the DMN relates to cognitive processing in a flexible manner and does not always act as a cohesive task-negative network in isolation.
Data availability
Raw data will not be publicly available due to reasons of data protection. Sharing of raw data requires a data sharing agreement, approved by the departments of legal affairs and data clearing of the Medical University of Vienna. Details about this process can be obtained from the corresponding author. Processed data are available at Dryad https://doi.org/10.5061/dryad.5qfttdzbd. Custom code is available at GitHub https://github.com/NeuroimagingLabsMUV/Godbersen2023_eLife.
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Data from: Task-evoked metabolic demands of the posteromedial default mode network are shaped by dorsal attention and frontoparietal control networksDryad Digital Repository, doi:10.5061/dryad.5qfttdzbd.
Article and author information
Author details
Rupert Lanzenberger
Funding
Austrian Science Fund (KLI610)
- Andreas Hahn
Medical University of Vienna (MDPhD Excellence Programm)
- Sebastian Klug
European Research Council (ERC-STG-716065)
- Anna Rieckmann
- Lars Stiernman
National Health and Medical Research Council (GN2001283)
- Luca Cocchi
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Ethics
Human subjects: All participants provided written informed consent after a detailed explanation of the study protocol, they were insured and reimbursed for participation. The study was approved by the Ethics Committee of the Medical University of Vienna (ethics number 1479/2015) and procedures were carried out according to the Declaration of Helsinki. The study was pre-registered at ClinicalTrials.gov (NCT03485066).
Copyright
© 2023, Godbersen et al.
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.
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