Fig. 7. Effects of anaesthetic treatment with CO₂. (A) The time schedule for the preference test (PT, open column) and training (Tr, filled column). In the training session, crickets were subjected to four trials of differential conditioning with an inter-trial interval (ITI) of 2 min. Crickets were anaesthetized with CO₂ for 60s before and at various times after training (striped bar on the time schedule). Odour preference was tested before (PT-1) and 5 h after (PT-2) training. (B) Performance indices of 14 groups of crickets 5 h after training. Values are means ± S.E.M. The open circle indicates the performance of the group that received training but no anaesthetic treatment (N=38), and the open square indicates the performance of the group that received anaesthetic treatment 1 h before training (N=17). Filled squares show the performances of 12 groups (N=21-27) that received anaesthetic treatment immediately (0 min) or 1-60 min after training.