Fig. 2. The early, brief type of visual evoked potential (VEP). (A) Five successive single sweeps (the 21st to 25th of a series) with 1 s trains of 10 Hz flashes eliciting early biphasic VEPs following the stimulus artifact (variable because of the digitizing rate). Note the small spike burst type of omitted stimulus potential (OSP) approximately 140 ms after the due-time. (B) The same sweeps averaged after rectifying to avoid negative-going and positive-going spikes cancelling each other. The slow wave average OSP is thus the result of summing spikes in this case.
