Multichannel Mapping of Spatial Distributions of Scalp Potential Fields Evoked by Checkerboard Reversal to Different Retinal Areas

Abstract

This paper will examine the components of potentials evoked by checkerboard reversal. The components will be defined in terms of latency and scalp location, and we will show changes of components as a function of retinal stimulus site. A considerable problem in conventional evoked potential assessment is the different potential waveshapes which are recorded from different electrode sites on the head (see Fig. 1). In addition, waveshapes at given electrode sites may change when a different reference is used. An example is shown in Fig. 1 where a set of simultaneously recorded evoked potential data from forty-seven electrodes is illustrated as waveforms using two different reference points, the mean of the ears or an anterior midline electrode (Fig. 1A and B). Of course, any one of the forty-seven channels could have been used as a reference, creating an immense number of different waveshapes out of the same data set.