Figure 2.

Light-alone trials 24 h after training extinguish fear memory but do not reverse the conditioning-induced increase in the surface expression of GluR1. Rats were conditioned with 10 light–shock pairings; they were given light-alone trials 24 h after training. Context control rats were returned to the startle box at the equivalent time without light-alone trials. Memory retention was assessed 24 h after light-alone trials. A, Representative blots and mean ± SEM of GluR1 immunoreactivities from rats decapitated 24 h after extinction training. LA and BLA tissues were dissected out, and the surface GluR1 levels were determined by biotin labeling. B, GluR1 levels in the context control and extinction groups were determined in synaptoneurosomes. Cont, Context; Wort, wortmannin; Veh, vehicle.