Examination of contour plots made with NeuroScan (V 4.3.1), and reviewing 3-D color maps of midline electrodes (Figure 2) created in Sigma Plot (v 7.0) revealed maximum amplitude for the P160 and P300 signals to be along midline electrodes, with the maxima for both peaking at Fz (Figure 3). Values extracted from this site were used for the subsequent statistical analysis; it is also important to note that the results were unchanged if measured at FCz, Cz, Cpz and Pz, but were attenuated at Oz.
