title: Application of the equiweight analysis method for the evaluation of the origin of the N1 and N2 waves of visual evoked potentials.
abstract: The applicability of the equiweight analysis method was studied with a view to evaluating the position in depth of the two dominating waves of the visual evoked potentials, recorded from the scalp of human subjects upon the appearance of a sinusoidal grating. The stimulus spatial frequency was 2, 4, 8 or 16 c/deg and its contrast was 0.2 or 0.3. The data of the topographic studies confirm earlier observations that the N1 wave with latency of about 100 ms was localized medially with maximum in Oz, while the N2 wave with latency of about 150 ms was spread over a wider area of the scalp. The results of the equiweight analysis corresponded to the evidence of cortical origin of N1. The wide propagation of the N2 wave proved to be an obstacle for the applicability of the method, although it seems promising when the source of the visual evoked potential is limited in area.
authors.affiliation: Institute of Physiology, Bulgarian Academy of Sciences, Sofia.
authors.forename: A
authors.initials: A
authors.lastname: Vassilev
authors.forename: V
authors.initials: V
authors.lastname: Stomonyakov
authors.forename: V
authors.initials: V
authors.lastname: Manahilov
authors.forename: D
authors.initials: D
authors.lastname: Mitov
authors.forename: A
authors.initials: A
authors.lastname: Gydikov
mesh_terms: D004566:Electrodes; D004569:Electroencephalography; D005074:Evoked Potentials, Visual; D005260:Female; D006801:Humans; D008297:Male; D013223:Statistics as Topic