Document Detail


Comparative power spectral analysis of simultaneous elecroencephalographic and magnetoencephalographic recordings in humans suggests non-resistive extracellular media.
MedLine Citation:
PMID:  20697790     Owner:  NLM     Status:  In-Process    
Abstract/OtherAbstract:
The resistive or non-resistive nature of the extracellular space in the brain is still debated, and is an important issue for correctly modeling extracellular potentials. Here, we first show theoretically that if the medium is resistive, the frequency scaling should be the same for electroencephalogram (EEG) and magnetoencephalogram (MEG) signals at low frequencies (<10 Hz). To test this prediction, we analyzed the spectrum of simultaneous EEG and MEG measurements in four human subjects. The frequency scaling of EEG displays coherent variations across the brain, in general between 1/f and 1/f(2), and tends to be smaller in parietal/temporal regions. In a given region, although the variability of the frequency scaling exponent was higher for MEG compared to EEG, both signals consistently scale with a different exponent. In some cases, the scaling was similar, but only when the signal-to-noise ratio of the MEG was low. Several methods of noise correction for environmental and instrumental noise were tested, and they all increased the difference between EEG and MEG scaling. In conclusion, there is a significant difference in frequency scaling between EEG and MEG, which can be explained if the extracellular medium (including other layers such as dura matter and skull) is globally non-resistive.
Authors:
Nima Dehghani; Claude Bédard; Sydney S Cash; Eric Halgren; Alain Destexhe
Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural; Research Support, Non-U.S. Gov't     Date:  2010-08-10
Journal Detail:
Title:  Journal of computational neuroscience     Volume:  29     ISSN:  1573-6873     ISO Abbreviation:  J Comput Neurosci     Publication Date:  2010 Dec 
Date Detail:
Created Date:  2010-11-12     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  9439510     Medline TA:  J Comput Neurosci     Country:  United States    
Other Details:
Languages:  eng     Pagination:  405-21     Citation Subset:  IM    
Affiliation:
Integrative and Computational Neuroscience Unit (UNIC), UPR2191, CNRS, Gif-sur-Yvette, France.
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MeSH Terms
Descriptor/Qualifier:
Grant Support
ID/Acronym/Agency:
EB009282/EB/NIBIB NIH HHS; NS18741/NS/NINDS NIH HHS; NS44623/NS/NINDS NIH HHS

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