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Modeling in magnetoencephalography (MEG) and electroencephalography (EEG) requires knowledge of the in vivo tissue resistivities of the head. The aim of this paper is to examine the influence of tissue resistivity changes on the neuromagnetic field and the electric scalp potential. A high-resolution finite element method (FEM) model (452,162 elements, 2-mm(More)
The influence of gray and white matter tissue anisotropy on the human electroencephalogram (EEG) and magnetoencephalogram (MEG) was examined with a high resolution finite element model of the head of an adult male subject. The conductivity tensor data for gray and white matter were estimated from magnetic resonance diffusion tensor imaging. Simulations were(More)
BACKGROUND The structure of the anatomical surfaces, e.g., CSF and gray and white matter, could severely influence the flow of volume currents in a head model. This, in turn, will also influence the scalp potentials and the inverse source localizations. This was examined in detail with four different human head models. METHODS Four finite element head(More)
Effects of soft skull bone, cerebrospinal fluid (CSF) and gray matter on scalp potentials were examined with highly heterogeneous finite element models of an adult male subject. These models were constructed from segmented T1 weighted magnetic resonance images. Models had voxel resolutions of 1x1x3.2 mm with a total of about 1.5 million voxels. The scalp(More)
The influence of volume currents on the magnetic field is an important question in magnetoencephalography since the spherical volume conductor is still widely used for source localization. In theory, the magnetic field of a radial dipole in a homogeneous sphere is zero. In realistic models of the head, the field is suppressed when compared with a tangential(More)
Pianists often report that pure listening to a well-trained piece of music can involuntarily trigger the respective finger movements. We designed a magnetoencephalography (MEG) experiment to compare the motor activation in pianists and nonpianists while listening to piano pieces. For pianists, we found a statistically significant increase of activity above(More)
Neither music nor spoken language form uniform auditory streams, rather, they are structured into phrases. For the perception of such structures, the detection of phrase boundaries is crucial. We discovered electroencephalography (EEG) and magnetoencephalography (MEG) correlates for the perception of phrase boundaries in music. In EEG, this process was(More)
To investigate the influence of anisotropic electrical conductivity in white matter on the forward and inverse solution in electroencephalography (EEG) and magnetoencephalography (MEG) numerical simulation studies were performed. A high-resolution (1 mm3 isotropic) finite element model of a human head was implemented to study the sensitivity of EEG and MEG(More)
OBJECTIVE Recent studies using electroencephalography or magnetoencephalography have shown that peripheral nerve stimulations produce short-latency high-frequency signals in the human somatosensory cortex. The present study tested whether they consist of more than one distinct type of signal. METHODS Somatic evoked magnetic fields (SEFs) elicited by(More)
Accurate resistivity values are necessary to construct reliable numerical models to solve forward/inverse problems in EEG and to localize activity centres in functional brain imaging. These models require accurate geometry and resistivity distribution. The geometry may be extracted from high resolution images. The resistivity distribution may be estimated(More)