Group II subjects had been taught the differences between the patterns but had not practiced the task. All achieved the learning level quickly and there were no non-learners.

Figure (3.6.1) Grand average ERPs elicited by the first fifty in light red and the last fifty in dark red. Recorded at (FZ), Y-axis shows amplitude in Microvolts (m n ), and X-axis shows latency in milliseconds (ms). The black vertical dotted line marks the point of stimulus onset, and the horizontal black dotted line represents the baseline. Upward deflection represents the negativity.

Figure (3.6.2) shows the top view cartoon brainmaps made from grand average ERP elicited by the first fifty trials subtracted from the last fifty trials stimuli. The numbers below each brainmap indicates the time in milliseconds when the map was computed. These results indicate 200 msec before stimulus to 1452 msec after stimulus. Color scale displays brain potentials from +15 m n in pink color, and –15 m n in dark blue. Frontal to the top, occipital to the bottom of the brain maps

The correct answer trials were more positive going than those were to the incorrect answer trials starting from 200msec to about 1200msec.

Figure (3.6.3.) Grand average ERPs elicited the correct answers in red color, and the incorrect answers in light red color. Recorded at (FZ), Y-axis shows amplitude in Microvolts (m n ), and X-axis shows latency in milliseconds (ms). The black vertical dotted line marks the point of stimulus onset, and the horizontal black dotted line represents the baseline. Upward deflection represents the negativity.

Figure (3.6.4) shows the top view cartoon brainmaps made from the grand average ERP elicited with the incorrect trials stimuli. The numbers below each brainmap indicates the time in milliseconds when the map was computed. These results indicate 200msec before stimulus to 1500msec after stimulus. Color scale displays brain potentials from +15 m n in pink color, and –15 m n in dark blue. Frontal to the top, occipital to the bottom of the brain maps.

Figure (3.6.5) shows the top view cartoon brainmaps made from the grand average ERP elicited with the correct trials stimuli. The numbers below each brainmap indicates the time in milliseconds when the map was computed. These results indicate 200msec before stimulus to 1500msec after stimulus. Color scale displays brain potentials from +15 m n in pink color, and –15 m n in dark blue. Frontal to the top, occipital to the bottom of the brain maps.

Multiple equal numbers of electrodes on each side of the scalp were used to record the ERP. Comparison between ERP elicited by the correct versus the incorrect and last fifty versus the first fifty trials answers showed the differences were more prominent in the frontal right-hand side than the left-hand side. These differences begin around 250msec post-stimulus and persist beyond the recording epoch of 1000msec in the right-hand hemisphere. The central electrodes shows differences started around 300msec and end very quickly at 500msec which I considered from my inspection and comparisons with other sides electrodes not significantly different where the traces were similar throughout the task. The parietal area electrodes showed positive differences starting around 450msec to beyond 1000msec. Amplitude of P300 was maximal in frontal and higher for the correct and last fifty trial answers and P600 showed maximal amplitude for correct last fifty in the parietal locations (Figure 3.6.6).

Figure (3.6.6) Grand average ERPs elicited by all subject’s performance in group II, recorded at F3-F4, C3-C4, and P3-P4 refer to linked mastoids, during the last fifty trials, Right-hand side traces represented in dark green color and left-hand side represented in light green color. Y-axis shows amplitude in Microvolts (m n ), and X-axis shows latency in milliseconds (ms). The black vertical dotted line marks the point of stimulus onset, and the horizontal black dotted line represents the baseline. Upward deflection represents the negativity.

Figure (3.6.8a) shows the left-hand side view spatial brainmaps made from group two grand average subtraction ERPs elicited with the correct minus the incorrect answers trials stimuli. The numbers below each large map indicates the time in milliseconds when the map was computed. The first time interval 250msec to 550msec and the second time interval 550msec to 850msec post-stimulus. Color scale displays brain potentials from +15 m n in pink color, and –15 m n in dark blue. The frontal area to the left-hand side and occipital area to the right-hand side of the brainmap.

Figure (3.6.8b) shows the right-hand side view spatial brainmaps made from group two grand average subtractions ERPs elicited with the correct minus the incorrect answer trial stimuli. The numbers below each large map indicates the time in milliseconds when the map was computed. The first time interval 250msec to 550msec and the second time interval 550msec to 850msec post-stimulus. Color scale displays brain potentials from +15 m n in pink color, and –15 m n in dark blue. The frontal area to the right-hand side and occipital area to the left-hand side of the brainmap.