Abstract:
:Directionality of signaling among brain regions provides essential information about human cognition and disease states. Assessing such effective connectivity (EC) across brain states using functional magnetic resonance imaging (fMRI) alone has proven difficult, however. We propose a novel measure of EC, termed metabolic connectivity mapping (MCM), that integrates undirected functional connectivity (FC) with local energy metabolism from fMRI and positron emission tomography (PET) data acquired simultaneously. This method is based on the concept that most energy required for neuronal communication is consumed postsynaptically, i.e., at the target neurons. We investigated MCM and possible changes in EC within the physiological range using "eyes open" versus "eyes closed" conditions in healthy subjects. Independent of condition, MCM reliably detected stable and bidirectional communication between early and higher visual regions. Moreover, we found stable top-down signaling from a frontoparietal network including frontal eye fields. In contrast, we found additional top-down signaling from all major clusters of the salience network to early visual cortex only in the eyes open condition. MCM revealed consistent bidirectional and unidirectional signaling across the entire cortex, along with prominent changes in network interactions across two simple brain states. We propose MCM as a novel approach for inferring EC from neuronal energy metabolism that is ideally suited to study signaling hierarchies in the brain and their defects in brain disorders.
journal_name
Proc Natl Acad Sci U S Aauthors
Riedl V,Utz L,Castrillón G,Grimmer T,Rauschecker JP,Ploner M,Friston KJ,Drzezga A,Sorg Cdoi
10.1073/pnas.1513752113subject
Has Abstractpub_date
2016-01-12 00:00:00pages
428-33issue
2eissn
0027-8424issn
1091-6490pii
1513752113journal_volume
113pub_type
杂志文章abstract::Opioid drugs produce their pharmacological effects by activating inhibitory guanine nucleotide-binding regulatory protein-linked mu, delta, and kappa opioid receptors. One major effector for these receptors is adenylyl cyclase, which is inhibited upon receptor activation. However, little is known about which of the te...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
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