Figure 6.

The RNAi effect is reversible. Two days after the injection of dsRNA (A; gray, dsNEG; white, dsNR1) or siRNA (B; gray, siNEG; white, siNR1), animals were subjected to three CS–US pairings (A1–A3). Memory was retrieved 2 h, 2 and 3 d after conditioning. In the dsRNA experiment, the animals were tested only once. Data from the acquisition phase were pooled for all subgroups (inset, n). The numbers on the bars represent the number of animals tested for each time point. In the siRNA experiment, n animals received multiple posttraining tests. PER, Percentage of animals that showed a PER during the CS presentation.