Fig. 6.

Sample period activity did not show associative selectivity, and did not change with learning. (A) All individual ROC values in novel blocks, before and after learning, for neurons selective in the sample period. Note the large number of neurons with ROC values between 0 and 0.5, indicating opposite selectivity as in familiar blocks. (B) Trial-by-trial ROC values, calculated in a seven-trial moving window in the sample period during novel blocks. (C) Average change in ROC values comparing all trials before the learning criterion and all trials after the learning criterion for neurons selective in the sample or delay phase. Error bars indicate SEM. (D, Right) average selectivity in the entire trial. (Left) Within-trial development of associative selectivity during novel blocks, calculated in a 200-ms and 10-trial window, advanced in steps of 50 ms and 1 trial. White lines mark beginning and end of sample period and delay period. Thick white line shows earliest appearance of selectivity strength of half the maximum selectivity in any given trial.