Figure 1.

Postreactivation administration of clonidine impairs reconsolidation of auditory fear memories. (a) Schematic of the experimental design. Rats received a single systemic injection of clonidine or its vehicle immediately after a reactivation session, and were tested for postreactivation long-term memory 1 day (PR-LTM) and 1 week later (PR-LTM 2). A dose of (b) 50 μg/kg (n=20), (c) 100 μg/kg (n=25) and (d) 200 μg/kg (n=20) was effective at impairing memory reconsolidation compared with the vehicle group (respectively, n=16, n=25, and n=20) as shown by an impaired conditioned response (freezing) at both time points. Bars represent mean±SEM freezing to the tone. Markers represent the mean±SEM freezing before the onset of the tone. Statistical significance: ^*p<0.05, ^**p<0.01, ^***p<0.001.