Figure 2.

Intra-ACC lidocaine infusions prevent memory consolidation, new learning, and memory retrieval. A) Experimental design showing timeline of schema training, new PA learning, and memory retrieval. Syringes indicate the time of bilateral intra-ACC infusions of 4% lidocaine [15 min before each session (S), S10–17]. B) PI during the acquisition of the OPAs and new PAs (S1–24). Lidocaine was injected bilaterally into the ACC during S10–17. PI rose to around 65% at S8 and decreased to around 50% (chance level) after lidocaine infusion (n = 6 rats/group). C) Nonrewarded cued-recall PTs for the acquisition of original schema across S3, S9, S18, and S24. The graph represents the percentage of dig time at the cued location (white bars) relative to that of the noncued locations (black bars). D) Memory recall in PT5 for the new PA (white bar) in aCSF and lidocaine infusion group, 24 h after a single session of training with 2 new PAs. E) Impact of intra-ACC lidocaine infusion on acquisition of new PAs in PT6 (lidocaine infusion 15 min before new PA acquisition; n = 6 rats/group) The graphs represents the percentage of dig time at the new cued location (white bars), the new noncued location (striped bars), and the old noncued locations (black bars) during PT6 after the aCSF and lidocaine infusion conditions. F) Impact of intra-ACC lidocaine infusion on retrieval of new PAs in PT4 by performing lidocaine or aCSF infusion 15 min before PT4 (lidocaine, n = 6 rats; aCSF, n = 5 rats). The graphs represent the percentage of dig time at the new cued location (white bars), the new noncued location (striped bars), and the old noncued locations (black bars) in the aCSF and lidocaine conditions. NPA, new PA; ns, not significant. Results are expressed as means ± sem. *P < 0.05; ***P < 0.001 for Student’s t tests comparing the proportion of digging for the cued PAs with the chance level of 16.67%, ^^^P < 0.001 for Student’s t tests comparing the proportion of cued digging in lidocaine vs. aCSF infused rats.