Spatial and temporal variations in eye-fixation-related potentials

When electroencephalograms (EEGs) are averaged at eye fixation pauses (at t he end of saccades), the specific brain potentials related to the visual in formation processing can be obtained. This eye-fixation-related potential ( EFRP) is a type of event-related potential. In this paper, the authors intr oduced two systems developed at their laboratory. The first measured the di stribution of EFRPs on the scalp with DC amplifiers in order to nullify eye movement artifacts. Three-dimensional EFRP topographies were obtained. The most prominent component (lambda response) of the waveform appeared at occ ipital sites. The second system was designed to examine the variation in EF RPs over time, using a sliding average method. The dynamic variation in EFR Ps could be observed as an animation. The sequence of variations in amplitu de was continuously displayed on a screen. This indicated the process of de crease and recovery of the lambda response generated by changes between per iods of brightness and darkness.