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Spatial and temporal resolutions of EEG: Is it really black and white? A scalp current density view.

Burle B, Spieser L, Roger C, Casini L, Hasbroucq T, Vidal F - Int J Psychophysiol (2015)

Bottom Line: While Current Source Density (CSD) estimates, through the Surface Laplacian (SL) computation, are well known to dramatically reduce volume conduction effects and hence improve EEG spatial resolution, its positive impact on EEG temporal resolution is much less recognized.In two simulation studies, we first show how volume conduction and reference electrodes distort the scalp potential time course, and how SL transform provides a much better spatio-temporal description.We then exemplify similar effects on two empirical datasets.

View Article: PubMed Central - PubMed

Affiliation: Aix-Marseille Université, CNRS, LNC UMR 7291, 13331 Marseille, France. Electronic address: boris.burle@univ-amu.fr.

No MeSH data available.


Simulation model. A–D. Graphic representation of the four meshes used as interface. A. Interface between CSF and brain. B. Between CSF and inner skull. C. Between outer skull and scalp. D. Between scalp and air. E–F. Location of the simulated dipoles, represented inside the head model. E. Top view. F. Lateral view.
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f0010: Simulation model. A–D. Graphic representation of the four meshes used as interface. A. Interface between CSF and brain. B. Between CSF and inner skull. C. Between outer skull and scalp. D. Between scalp and air. E–F. Location of the simulated dipoles, represented inside the head model. E. Top view. F. Lateral view.

Mentions: The head model used here was based on a segmentation of the MNI152 template brain and the leadfield and forward solution were computed with the OpenMEEG software (Gramfort et al., 2010; Kybic et al., 2005), which is based on a symmetric Boundary Element Method. Four nested layers were modeled (Fig. 2A–D): the brain envelope (smoothed outer part of the brain), the cerebro-spinal fluid (CSF), the outer skull and the scalp. The conductivity of air was set to 0. The other conductivities are relative, and the conductivity of the skull was set to .03 of the brain, while the CSF conductivity was set to 3 (3 times the brain and skin one, both set to 1). Sixty-four electrodes were modeled, located on the standard extended 10–20 system positions (Fig. 2E–F).


Spatial and temporal resolutions of EEG: Is it really black and white? A scalp current density view.

Burle B, Spieser L, Roger C, Casini L, Hasbroucq T, Vidal F - Int J Psychophysiol (2015)

Simulation model. A–D. Graphic representation of the four meshes used as interface. A. Interface between CSF and brain. B. Between CSF and inner skull. C. Between outer skull and scalp. D. Between scalp and air. E–F. Location of the simulated dipoles, represented inside the head model. E. Top view. F. Lateral view.
© Copyright Policy - CC BY
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4548479&req=5

f0010: Simulation model. A–D. Graphic representation of the four meshes used as interface. A. Interface between CSF and brain. B. Between CSF and inner skull. C. Between outer skull and scalp. D. Between scalp and air. E–F. Location of the simulated dipoles, represented inside the head model. E. Top view. F. Lateral view.
Mentions: The head model used here was based on a segmentation of the MNI152 template brain and the leadfield and forward solution were computed with the OpenMEEG software (Gramfort et al., 2010; Kybic et al., 2005), which is based on a symmetric Boundary Element Method. Four nested layers were modeled (Fig. 2A–D): the brain envelope (smoothed outer part of the brain), the cerebro-spinal fluid (CSF), the outer skull and the scalp. The conductivity of air was set to 0. The other conductivities are relative, and the conductivity of the skull was set to .03 of the brain, while the CSF conductivity was set to 3 (3 times the brain and skin one, both set to 1). Sixty-four electrodes were modeled, located on the standard extended 10–20 system positions (Fig. 2E–F).

Bottom Line: While Current Source Density (CSD) estimates, through the Surface Laplacian (SL) computation, are well known to dramatically reduce volume conduction effects and hence improve EEG spatial resolution, its positive impact on EEG temporal resolution is much less recognized.In two simulation studies, we first show how volume conduction and reference electrodes distort the scalp potential time course, and how SL transform provides a much better spatio-temporal description.We then exemplify similar effects on two empirical datasets.

View Article: PubMed Central - PubMed

Affiliation: Aix-Marseille Université, CNRS, LNC UMR 7291, 13331 Marseille, France. Electronic address: boris.burle@univ-amu.fr.

No MeSH data available.