KAO LIANG CHOW 



521 



shock was turned on for 5 seconds. The EEG was turned on again and the 

 opaque screen was removed to expose the stimulus for 2 seconds. If there 

 were EEG after-discharges during the two-second period, the stimulus 

 box was pushed forward for the animal to respond. If no after-discharges 



C2 



12 3 4 5 



M2 



VH ; 



2 3 4 5 



BILAT. 

 UNILAT. 



Fig. 8 

 Learning curves of four monkeys on four visual discrimin- 

 ations, first during bi-tcmporal seizure after-discharges (con- 

 tinuous line) and later during unilateral temporal seizure 

 (interrupted line). Percentages of correct responses are plotted 

 against successive two-day results (thirty trials). I to 5 refers 

 to thirty trial blocks. T.C., triangle v. circle; V.H., vertical v. 

 horizontal striations; BILAT, bilateral temporal after-discharges; 

 UNILAT, unilateral temporal after-discharges. 



appeared, the stimulus box was not pushed forward and the trial was 

 discounted (less than lo per cent of the total trials). Fifteen shock trials 

 were given every day with at least 5 minutes interval between trials. The 

 seizure after-discharges in the temporal cortex were similar to those 



