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. 2015 Nov 4;41(6):1569–1578. doi: 10.1038/npp.2015.315

Figure 1.

Figure 1

Results: sympathetic fear responses and explicit memory for fearful events. A single dose of propranolol before extinction learning eliminated learned fear responses, resulted in a subsequent loss of fear, prevented the return of fear, and attenuated explicit memory of the fearful events one day later in the absence of drug. Placebo group (solid bars), propranolol group (open bars), CS+ (red), CS− (blue), error bars reflect SEM. Critical test scores per task are: Conditioning (panel 1): Late phase (trials 7–12) over both groups (paired-samples T-test t(45)=−2.356, p=0.023); Extinction (panel 2): Early phase (trials 1–6) placebo group (paired-samples T-test t(23)=5.127, p<0.001), propranolol group (t(21)=1.054, p=0.308), and Late phase (trials 7–12) placebo group (t(23)=1.147, p=0.263), propranolol group (t(21)=1.341, p=0.194), and no absolute group differences in responses to CS+ or CS− trials in the early nor in the late phase were revealed by independent-samples T-tests; early phase CS+ (t(44)=−1.138, p=0.261), early phase CS− (t(44)=0.493, p=0.624), late phase CS+ (t(44)=−0.813, p=0.420), and late phase CS− (t(44)=−1.065, p=0.293); Recall (panel 3): As the recall paradigm is principally a second extinction session, extinction learning can be expected to occur rapidly. To maximize sensitivity to detect spontaneous recovery effects, we therefore calculated for each CS type (CS+, CS−) the average skin conductance for the early phase (trials 1–4), middle phase (trials 5–8), and late phase (9–12). Early phase placebo group (paired T-test t(23)=5.127, p<0.001), propranolol group (t(21)=1.515, p=0.145)); Re-extinction (fourth panel): a reinstatement score was calculated as the difference between the first re-extinction trial and the last trial of the recall task for the CS+ and CS− for each participant. Note, reinstatement (4 unsignaled shocks) occurred between recall and re-extinction. Placebo group (paired T-test t(23)=2.005, p=0.057), propranolol group (t(20)=−1.371, p=0.186), independent-samples T-tests for CS+ (t(37.021)=2.991, p=0.004) and CS− (t(43)=0.232, p=0.818). Contingency questionnaire (Panel 5): At the end of day 3, participants who had received propranolol on day 2 underestimated the number of shocks they had received following CS+ presentations on day 1 (independent samples T-tests day 1 CS+ t(43)=−2.560, p=0.014, CS−t(43)=0.453, p=0.653). Dotted line represents the actual number of received shocks on day 1. CS, conditioned stimulus.