Figure 2.
Propranolol does not facilitate extinction learning or erase fear memory. Injection of propranolol (arrow) prior to partial extinction on day 2 led to a significant decrease in fear expression as measured by (A) percent freezing and (B) bar-press suppression. There were no differences between groups in further extinction sessions on day 3 and day 5. Two unpaired shocks on day 5 reinstated fear on day 6 equally in both groups. Data shown in blocks of 2 trials. (conditioning: Cond; extinction: Ext; reinstatement: Reinst; day 2: D2)