[Role of filtration in localization of the evoked potential dipoles in the human brain: experiment and simulation].
3D dipole tracing with 1 ms step of visual evoked potentials recorded from 40 electrodes was performed under exposition of crosses in 5 healthy human subjects. The data on dipole displacement were compared with prediction of the simulation study on distortion of dipole localization by the signal filtration in the low-frequency band. These predictions were experimentally confirmed: the effect depends on the degree of filtration (0.1 or 0.5 Hz) and on the latency of EP waves. Localization and strength of P1 dipoles were not changed under filtration, while for later components--N2 and especially P3--they changed significantly. For the improvement of these distortions time constant of the amplification tract must be some times longer than the time of the dipole activity.
Frolov
A A
AA
Mikhaĭlova
E S
ES
Prokopenko
R A
RA
Shevelev
I A
IA
Slavutskaia
A V
AV
Konyshev
V A
VA
D001921:Brain / Q000502:physiology*; D004569:Electroencephalography; D004585:Electrooculography; D005074:Evoked Potentials, Visual / Q000502:physiology*; D005374:Filtration; D006801:Humans; D009482:Neurophysiology; D014796:Visual Perception / Q000502:physiology