The Dorsolateral Periaqueductal Gray and Its Role in Mediating Fear Learning to Life Threatening Events
Figure 8
Experiment 5– Effects of dorsal premammillary nucleus blockade on dlPAG-NMDA OFC acquisition.
The experimental design used is outlined above the graph, where vertical arrows show when the animals received the PMd and dlPAG infusions and were placed in a conditioning box with the olfactory CS. Histograms represent the mean (+SEM) of the percentage of approach time (A), hide time (B), and head-out time (C). The hatched horizontal line represents the mean and the confidence limits (within 95%) for the familiarization session in the odor box. Subjects were first submitted to an infusion into the PMd with PBS (PBS group, n = 6) or atenolol 40 pmol (ATE 40 pmol group, n = 6), and, after 5 min, were microinjected with NMDA 100 pmol into the dlPAG paired with amyl acetate odor during 10 min in the conditioning session. CS1 represents the first-order CS exposure and CS2 represents the second-order context (no odor) exposure. *p<0.05 compared with the PBS group (repeated measures ANOVA followed by Newman-Keuls test).