Figure 1. STD-LTD requires the activation of CB1 receptors.

(A) Schematic representation of the experimental design. (B) The stimulation of granule cells in the dentate gyrus followed the postsynaptic spike by 50 ms. (C) MF-GPSCs evoked before, after pairing, after addition of L-AP4 or L-AP4 plus picrotoxin (PTX), in the absence (Control) or in the presence of AM251 (each trace is the average of 30–60 trials including failures). (D) Mean GPSCs amplitude (before and after pairing, arrows at time 0) is plotted against time. Open circles: control (n = 44); closed circles: in the presence of AM251(n = 12); vertical bars are SEM. (E) Paired-pulse ratio measured before (Control) and after pairing in neurons exhibiting LTD (grey STD-D; n = 12). ***p<0.001. (F) Plot of 1/CV² versus GPSCs amplitude measured after LTD induction and normalized to respective controls. The closed circle indicate the mean (SEM is within the symbols).