Figure 2.

SCRs showing facilitated fear memory consolidation by DCS. (a) Day 1: Significantly larger SCRs to the CS+ than to the CS− during late fear conditioning in context A indicate learning of the CS+−UCS contingency (fear memory) in context A on day 1. A reversal of the conditioning effect during late extinction in context B indicates learning of the CS+−noUCS contingency (extinction memory) in context B. (b) Day 2: SCRs to the CS+ in the conditioning context were again significantly larger than to the CS− on day 2, but only in those subjects receiving DCS after learning on day 1. A similar effect was apparent in the extinction context, that is, there was no evidence for extinction memory recall. Scale: z scores (unit: standard deviations [SDs]). *P < 0.05, (*)P < 0.1, 1-tailed t-test versus 0.