Figure 6.

Instrumental choice test performance in experiment 2. A and C show responses to the omission-cue producing and no-consequence chains in group O-SC, and B and D show responses to the control-cue and no-consequence chains in group OC-S. E shows cue preference ratios (cue-producing responses/total responses), normalized by training performance (test preference ratio/preference ratio in the final 2 training sessions). *p < 0.05, significantly lower preference ratios in sham-lesioned rats of group O-SC than in any of the other three lesion/training groups. The group designations indicate the nature of training received. Group O-SC (n = 9 lesions and 7 shams) received training with a food-omission cue and a control cue unpaired with shock, and group OC-S (n = 9 lesions and 6 shams) received training with a shock-paired cue and a control cue unpaired with food or food omission.