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. Author manuscript; available in PMC: 2016 Sep 22.
Published in final edited form as: Neuropsychopharmacology. 2015 Oct 14;41(6):1569–1578. doi: 10.1038/npp.2015.315

Figure 1. Results sympathetic fear responses and explicit memory for fearful events.

Figure 1

A single dose of propranolol prior to extinction learning eliminated learned fear responses, resulted in a subsequent loss of fear, prevented the return of fear, and attenuated explicit memory of the fear full events one day later in the absence of drug. Placebo group (solid bars), propranolol group (open bars), CS+ (red), CS− (blue), error bars reflect s.e.m. Critical test scores per task are: Conditioning (panel 1): Late phase (trial 7-12) over both groups (paired samples T-test t(45) = −2.356, p = 0.023); Extinction (panel 2): Early phase (trial 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 (trial 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 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), 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 (fifth panel): At the end of Day 3, participants who had received propranolol on Day 2 underestimated the number of shocks they had received following CS+ presentation 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.