Fig. 1

a Rats were divided into four groups, two receiving vehicle (Veh) infusion prior to either memory retrieval (Ret) or returned to the home cage (NoRet), and two receiving the D1R antagonist Schering-23390 (Sch) before retrieval or returned to home cage. b All groups acquired fear conditioning across CS-US presentations to an equal extent. c There was no difference in freezing between the two Ret groups, suggesting acute Sch infusion into the BLA had no effect on freezing expression itself. d All groups extinguished responding to the CS over time. e Following extinction all groups had reduced fearful behavior to the CS to an equivalent level. At the end of the CS the US was presented again for fear reacquisition (ReAcq). f The effects of reactivation (Ret) and/or Sch on the long term memory (LTM) of fear were tested 24 h later. Only the groups pre-treated with Sch appeared to have a retrieval-extinction effect on fear reacquisition. **p < 0.001