N100 Frontal Component and Influence of Reference Location in Pattern Visual Evoked Potential Studied with the Area Display Technique

Abstract

The literature in the area of photic and pattern visual evoked potentials makes only scant reference to the distribution of potentials that appear beyond the primary visual area (Allison et al. 1977; Lehmann and Skrandies 1980; Skran-dies 1986). A few recent reports (Hajdukovic etal. 1984; Spitz etal. 1986; Guidi and Bickford 1987) pointed out the existence of a negative frontal component that occurs about the same time as the occipital PI 00 in the majority of normal and pathological observations. This finding raises doubt about the relative inactivity of the midfrontal (MF) electrode as reference. In this study, the first aim was to evaluate the influence of different reference locations (cephalic and non-cephalic) in the recording of the 16 primary evoked responses and the possible change in interpretation that contour mapping could produce. The second aim was to define the spread of the N100 frontal component and to achieve some insight into the origin of this wave.