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Title:

Fronto-parietal connectivity is a non-static phenomenon with characteristic changes during unconsciousness.

Document type:
Journal Article; Article
Author(s):
Untergehrer, Gisela; Jordan, Denis; Kochs, Eberhard F; Ilg, Rüdiger; Schneider, Gerhard
Abstract:
It has been previously shown that loss of consciousness is associated with a breakdown of dominating fronto-parietal feedback connectivity as assessed by electroencephalogram (EEG) recordings. Structure and strength of network connectivity may change over time. Aim of the current study is to investigate cortico-cortical connectivity at different time intervals during consciousness and unconsciousness. For this purpose, EEG symbolic transfer entropy (STEn) was calculated to indicate cortico-cortical information transfer at different transfer times.The study was performed in 15 male volunteers. 29-channel EEG was recorded during consciousness and propofol-induced unconsciousness. EEG data were analyzed by STEn, which quantifies intensity and directionality of the mutual information flow between two EEG channels. STEn was computed over fronto-parietal channel pair combinations (10 s length, 0.5-45 Hz total bandwidth) to analyze changes of intercortical directional connectivity. Feedback (fronto -> parietal) and feedforward (parieto -> frontal) connectivity was calculated for transfer times from 25 ms to 250 ms in 5 ms steps. Transfer times leading to maximum directed interaction were identified to detect changes of cortical information transfer (directional connectivity) induced by unconsciousness (p<0.05).The current analyses show that fronto-parietal connectivity is a non-static phenomenon. Maximum detected interaction occurs at decreased transfer times during propofol-induced unconsciousness (feedback interaction: 60 ms to 40 ms, p = 0.002; feedforward interaction: 65 ms to 45 ms, p = 0.001). Strength of maximum feedback interaction decreases during unconsciousness (p = 0.026), while no effect of propofol was observed on feedforward interaction. During both consciousness and unconsciousness, intensity of fronto-parietal interaction fluctuates with increasing transfer times.Non-stationarity of directional connectivity may play a functional role for cortical network communication as it shows characteristic changes during propofol-induced unconsciousness.
Journal title abbreviation:
PLoS ONE
Year:
2014
Journal volume:
9
Journal issue:
1
Pages contribution:
e87498
Language:
eng
Fulltext / DOI:
doi:10.1371/journal.pone.0087498
Pubmed ID:
http://view.ncbi.nlm.nih.gov/pubmed/24475298
Print-ISSN:
1932-6203
TUM Institution:
Klinik für Anästhesiologie (DHM); Neurologische Klinik und Poliklinik
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