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. 2020 Jan 31;11:628. doi: 10.1038/s41467-020-14461-3

Fig. 4. Two learning events spaced by 24 h or 48 h result in long-term memory expression.

Fig. 4

a Rats were either left in their home cage (naive, N; n = 5), exposed to a shock-only protocol (n = 6) or received two training trials, one at PN17 (Tr1) and the second at PN18 (Tr2) (PN17 + PN18; n = 9). Rats were tested 1 day after the second training (T1) and again 5 days later (T2) or at matched time points for the other 2 groups. b Rats received either one training trial (Tr1) at PN17 (n = 6) or at PN19 (n = 8), or two training trials, one at PN17 (Tr1) and the second at PN19 (Tr2) (PN17 + PN19; n = 8). Rats were tested 1 day after the last training (T1) and again at PN24 (T2). c Rats received two training trials, one at PN17 and the second 6 h later (2xPN17; n = 6), or one at PN18 and the second 6 h later (2xPN18; n = 7), or one training at PN17 and the second at PN18 (PN17 + PN18; n = 9). The animals were tested 1 day after the last training (T1) and again at PN24 (T2). d Rats (n = 10) were trained at PN17 (Tr1), and again at PN18 (Tr2), and then tested 29 days later (T1). e Rats received two training trials, one at PN17 (Tr1) and the second at PN18 (Tr2). Rats were injected twice (black arrows) in the dHC with either SCR (n = 6) or AS (n = 6) against PSD-95 immediately after training at PN17 and 6 h later. Rats were tested at PN19 (T1), and at PN24 (T2). At T2, upon entering the shock compartment, rats were trained again (Tr) and tested 1 day later (T3). Memory retention is expressed as mean latency ± s.e.m. (in seconds, s). *P < 0.05 (one-way RM ANOVA followed by Tukey’s multiple comparisons test); ***P < 0.001 (two-way RM ANOVA followed by Bonferroni’s multiple comparisons test). For detailed statistical information, see Supplementary Table 7.