E. Bark

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The aim of the study was to obtain some experimental evidence of the 'scanning hypothesis' that links electroencephalogram (EEG) alpha-activity with rhythmically spreading waves in the visual cortex. The hypothesis was tested in experiments with 29 healthy adults. Under flicker stimulation through closed lids with the frequency of the individual(More)
In order to create a brain-computer interface (BCI) on the basis of paradigm P300 (the so-called Farwell-Donchin paradigm, FD) with a symbolical matrix used as stimuli, there were compared characteristics of event-related potentials (ERP) obtained from stimulation both by symbolical and alphabetical matrixes. The matrixes contained 6 x 6 signs (cyrillic(More)
In order to create a P300-based brain-computer interface (BCI) (the so-called Farwell-Donchin paradigm, FD) with a symbol matrix used as a stimulus, we compared characteristics of event-related potentials (ERPs) in response to stimulation by 6 × 6 matrices composed of either pictogram symbols or Cyrillic alphabet characters. Nine healthy adults were(More)
Dynamic study of 3D localization of the equivalent current dipoles (ECD)--sources of the EEG alpha rhythm in the human brain was performed in seven subjects with closed eyes using a one-dipole model. An exact localization of ECDs was obtained by combination of EEG and MRI mapping that allowed tracing of ECD shifts over the cortex with 4 ms step. Our data(More)
The numbers of alpha-rhythm equivalent current dipoles (ECD) arising in the human brain before and during rhythmic photostimulation at the alpha-rhythm frequency was studied in six healthy adult subjects. Dipoles were calculated using a single-dipole model for the whole of the alpha-range and three subranges by solution of inverse equations in a three-layer(More)
Dynamic study of the equivalent current dipoles (ECDs) of alpha rhythm in the human brain was performed in a one-dipole model. The number of ECDs was shown to be dependent on the time course of visual stimulation, on the phase shift of triggering of flickers with alpha-rhythm frequency from alpha-wave, as well as on the type of visual illusions produced in(More)
Exact localization of equivalent current dipoles (ECD) was obtained by combining the EEG and the MRI mapping allowing to trace the ECG displacement over the cortex. The data obtained corroborate localization of the alpha-rhythm ECD in the Gyrus Calcarina: the human primary visual cortex. Successive shifts of the ECD over this area during generation of each(More)
In 11 subjects the dynamic localization (with 2-ms step) of the equivalent current dipole of alpha rhythm during travelling alpha waves was studied using one-dipole 3-layered spherical head model and MRI. The dipole was localized in the occipital cortex and during the development of a single alpha wave it shifted in one or another direction while dipole's(More)
In computer-controlled experiments the visual illusions were studied which appeared in human subjects under conditions of diffuse rhythmic photostimulation through the closed eyes with the individual dominant alpha-rhythm frequency. A significant correlation was demonstrated between the type of experienced illusion (or its absence) and the trajectory of the(More)
Under flicker stimulation through the closed eyes, synchronized with different phases of the EEG alpha wave, all 18 subjects systematically perceived the illusory visual objects (ring, circle, spiral, or curvilinear grid). Most frequently, they saw a ring or a circle, a little less frequently, a three-dimensional spiral, and at last-a curvilinear grid. The(More)