Figure 5.

Habitual-like avoidance responding with respect to the positive contingency between the response and safety signal. (A) The effects of systemic morphine on the mean SQRT transformed avoidance responses per min during a drug-free extinction test. (B) The safety signal was then presented following lever press avoidance responses after the first 10 min of the extinction session. This test manipulation was conducted in two groups, the paired group that had received prior pairings of the safety signal and morphine or the unpaired groups where presentations of the safety signal and administration of morphine were across sessions. Each bar represents the mean of the SQRT transformed rate of avoidance responses per minute ± SEM. Graph insets depict the mean untransformed avoidance responses per minute ± SEM for each experiment.