The activity of AWC neurons during recovery is important for forgetting adaptation. A, Retention of olfactory adaptation to pyrazine in wild-type and tir-1 (tm3036) animals (n = 6). B, Retention of olfactory adaptation to pyrazine in wild-type animals expressing the Drosophila histamine-gated chloride channel in AWC neurons. The timing of application of histamine is shown in the figure. Chemotaxis of naive, adapted, and 4-h-recovered animals was analyzed (n = 12). C, Quantification of Ca²⁺ responses in AWA neurons of wild-type animals expressing histamine-gated chloride channels in AWC neurons (n ≥ 8). Data were normalized to the averages in the naive animals. **p < 0.01; t test with Bonferroni's correction (A) or Student's t test (B, C). Error bars represent SEM.