Effect of skull discontinuities on MEG: experimental results

Abstract

Event Abstract Back to Event Effect of skull discontinuities on MEG: experimental results Stephan Lau1*, Lars Flemming2, Levin Kuhlmann3 and Jens Haueisen1 1 Technical University Ilmenau, Germany 2 University Jena, Biomagnetic Center, Germany 3 University of Melbourne, Neuroengineering, Australia Neuronal activity in the brain is often analyzed based on magneto- and electroencephalographic recordings (MEG, EEG). Skull discontinuities, such as fontanelles of the neonate skull or post-surgical skull conditions, are known to influence the EEG. However, their influence on the MEG has rarely been analyzed quantitatively. Our aim is to characterize and quantify the effect of skull discontinuities on the MEG. We constructed an artificial miniaturized coaxial dipole and implanted it in rabbit brains. We recorded a 4x4-channel magnetoencephalogram (MicroSQUID) of the activity produced by an impressed sinusoidal current (0.1mA at 20 Hz) under three conditions: (1) an intact skull, (2) with a 5x5 mm skull hole filled with agarose gel of conductivity equivalent to skin (0.33 S/m) (3) with the same hole filled with agarose gel of conductivity of cerebrospinal fluid (CSF) (1.57 S/m) respectively. The exact position of the source was determined from a CT coregistered with the MEG in a stereotactic coordinate system. Results show that the introduction of a hole in the skull filled with agar of skin conductivity can cause an MEG magnitude deviation (MAGrel) of 5-30% depending on the skull and hole properties, and the depth, position and orientation of the source relative to the hole. CSF-type agarose gel instead of the skin-type one can alter the MEG magnitude by an additional 5-15%. We conclude that discontinuities in the skull should be accounted for in volume conductor models used in the reconstruction of amplitudes of brain sources from MEG, particularly in infants, children and patients with post-surgical skull conditions. Conference: Biomag 2010 - 17th International Conference on Biomagnetism , Dubrovnik, Croatia, 28 Mar - 1 Apr, 2010. Presentation Type: Poster Presentation Topic: Instrumentation and Multi-modal Integrations: MEG, Low-field MRI,EEG, fMRI,TMS,NIRS Citation: Lau S, Flemming L, Kuhlmann L and Haueisen J (2010). Effect of skull discontinuities on MEG: experimental results. Front. Neurosci. Conference Abstract: Biomag 2010 - 17th International Conference on Biomagnetism . doi: 10.3389/conf.fnins.2010.06.00429 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 09 Apr 2010; Published Online: 09 Apr 2010. * Correspondence: Stephan Lau, Technical University Ilmenau, Ilmenau, Germany, stephan.lau@adelaide.edu.au Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Stephan Lau Lars Flemming Levin Kuhlmann Jens Haueisen Google Stephan Lau Lars Flemming Levin Kuhlmann Jens Haueisen Google Scholar Stephan Lau Lars Flemming Levin Kuhlmann Jens Haueisen PubMed Stephan Lau Lars Flemming Levin Kuhlmann Jens Haueisen Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.