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Document type:
Journal Article; Article
Author(s):
Jordan, D; Ilg, R; Riedl, V; Schorer, A; Grimberg, S; Neufang, S; Omerovic, A; Berger, S; Untergehrer, G; Preibisch, C; Schulz, E; Schuster, T; Schröter, M; Spoormaker, V; Zimmer, C; Hemmer, B; Wohlschläger, A; Kochs, EF; Schneider, G
Title:
Simultaneous electroencephalographic and functional magnetic resonance imaging indicate impaired cortical top-down processing in association with anesthetic-induced unconsciousness.
Abstract:
In imaging functional connectivity (FC) analyses of the resting brain, alterations of FC during unconsciousness have been reported. These results are in accordance with recent electroencephalographic studies observing impaired top-down processing during anesthesia. In this study, simultaneous records of functional magnetic resonance imaging (fMRI) and electroencephalogram were performed to investigate the causality of neural mechanisms during propofol-induced loss of consciousness by correlating FC in fMRI and directional connectivity (DC) in electroencephalogram.Resting-state 63-channel electroencephalogram and blood oxygen level-dependent 3-Tesla fMRI of 15 healthy subjects were simultaneously registered during consciousness and propofol-induced loss of consciousness. To indicate DC, electroencephalographic symbolic transfer entropy was applied as a nonlinear measure of mutual interdependencies between underlying physiological processes. The relationship between FC of resting-state networks of the brain (z values) and DC was analyzed by a partial correlation.Independent component analyses of resting-state fMRI showed decreased FC in frontoparietal default networks during unconsciousness, whereas FC in primary sensory networks increased. DC indicated a decline in frontal-parietal (area under the receiver characteristic curve, 0.92; 95% CI, 0.68-1.00) and frontooccipital (0.82; 0.53-1.00) feedback DC (P<0.05 corrected). The changes of FC in the anterior default network correlated with the changes of DC in frontal-parietal (rpartial=+0.62; P=0.030) and frontal-occipital (+0.63; 0.048) electroencephalographic electrodes (P<0.05 corrected).The simultaneous propofol-induced suppression of frontal feedback connectivity in the electroencephalogram and of frontoparietal FC in the fMRI indicates a fundamental role of top-down processing for consciousness.
Journal title abbreviation:
Anesthesiology
Year:
2013
Journal volume:
119
Journal issue:
5
Pages contribution:
1031-42
Language:
eng
Fulltext / DOI:
doi:10.1097/ALN.0b013e3182a7ca92
Pubmed ID:
http://view.ncbi.nlm.nih.gov/pubmed/23969561
Print-ISSN:
0003-3022
TUM Institution:
Fachgebiet Neuroradiologie (Prof. Zimmer); Klinik für Anästhesiologie (DHM); Klinik und Poliklinik für Nuklearmedizin; Neurologische Klinik und Poliklinik
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