Source derivation: application to topographic mapping of visual evoked potentials.

The application of a source derivation technique to topographic mapping of the pattern-reversal visual evoked potential is described. Comparisons were made with non-cephalic and common average reference recordings. Source derivation yielded wave forms which were less influenced by activity of reference origin. Source derivation wave forms were similar to those obtained with common average referencing but contour plots showed less spread of regions of maximal activity in the case of source derivation. It is suggested that source derivation may be useful in further studies of the topography and sources of cerebral evoked potentials.