Fig. 3. Variations among preparations. (A) Single sweeps from six animals. The loci in each case gave no visual evoked potential (VEP) but a good omitted stimulus potential (OSP), appearing as a spike burst, and all having a similar latency after the due-time. The OSP is seen whether the stimulus is in the middle of a train or at its end. (B) Some loci (here demonstrated from a seventh preparation) show slow waves overshadowing the spike bursts, in this case also giving VEPs. Four successive trains are shown, all at 15 Hz, with only the last four flashes in single sweeps.
