Default‐mode network functional connectivity is closely related to metabolic activity |
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Authors: | Tom Christian Adamsen Martin Biermann Njål Brekke Alexander Richard Craven Lars Ersland Renate Grüner Nina Kleven‐Madsen Ole‐Heine Kvernenes Thomas Schwarzlmüller Rasmus Aamand Olesen Kenneth Hugdahl |
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Institution: | 1. Department of Radiology, Haukeland University Hospital, Bergen, Norway;2. Department of Chemistry, University of Bergen, Bergen, Norway;3. Department of Clinical Medicine, University of Bergen, Bergen, Norway;4. Department of Oncology and Medical Physics, Haukeland University Hospital, Bergen, Norway;5. Department of Biological and Medical Psychology, University of Bergen, Bergen, Norway;6. NORMENT Center of Excellence, University of Oslo, Norway;7. Department of Clinical Engineering, Haukeland University Hospital, Bergen, Norway;8. Department of Physics and Technology, University of Bergen, Bergen, Norway;9. Center of Functionally Integrative Neuroscience and MINDLab, Aarhus University, Aarhus, Denmark;10. Division of Psychiatry, Haukeland University Hospital, Bergen, Norway |
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Abstract: | Over the last decade, the brain's default‐mode network (DMN) and its function has attracted a lot of attention in the field of neuroscience. However, the exact underlying mechanisms of DMN functional connectivity, or more specifically, the blood‐oxygen level‐dependent (BOLD) signal, are still incompletely understood. In the present study, we combined 2‐deoxy‐2‐18F]fluoroglucose positron emission tomography (FDG‐PET), proton magnetic resonance spectroscopy (1H‐MRS), and resting‐state functional magnetic resonance imaging (rs‐fMRI) to investigate more directly the association between local glucose consumption, local glutamatergic neurotransmission and DMN functional connectivity during rest. The results of the correlation analyzes using the dorsal posterior cingulate cortex (dPCC) as seed region showed spatial similarities between fluctuations in FDG‐uptake and fluctuations in BOLD signal. More specifically, in both modalities the same DMN areas in the inferior parietal lobe, angular gyrus, precuneus, middle, and medial frontal gyrus were positively correlated with the dPCC. Furthermore, we could demonstrate that local glucose consumption in the medial frontal gyrus, PCC and left angular gyrus was associated with functional connectivity within the DMN. We did not, however, find a relationship between glutamatergic neurotransmission and functional connectivity. In line with very recent findings, our results lend further support for a close association between local metabolic activity and functional connectivity and provide further insights towards a better understanding of the underlying mechanism of the BOLD signal. Hum Brain Mapp 36:2027–2038, 2015. © 2015 Wiley Periodicals, Inc. |
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Keywords: | FDG‐PET resting‐state fMRI 1H‐MR spectroscopy default‐mode network resting‐state functional connectivity |
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