Fig. 4.

Novelty promotes LTM in specific inputs: regional and temporal requirements. (A) Saccharin consumption in the test session is expressed as mean percentage ± SEM relative to acquisition session. (Left) Animals were subjected to a weak CTA training session and exposed to a novel OF 60 min before or 150 min after saccharin intake (n = 8 and 12). Control animals (n = 13) did not explore the arena. P > 0.05, one-way ANOVA. (Right) Animals were subjected to a weak CTA training and drank, or not (Control, n = 13), NaCl (0.3%) (n = 11) or water (H₂O, n = 7) 150 min after saccharin intake. *, P < 0.05 vs. all groups, Newman-Keuls after one-way ANOVA. (B) Rats were deprived of water for 24 h and then habituated to drink water from a graduated tube twice a day for 2 days. The next day animals received a 4 min SOR training 1 h after the consumption of water (H₂O, n = 9), a novel taste (NaCl, n = 8) or the exposure to a novel open field (OF, n = 8). Control rats did not drink water (n = 8). SOR-LTM was tested 24 h after training. Exploration time is expressed as mean ± SEM. ***, P < 0.001 vs. all test sessions, Newman-Keuls after one-way ANOVA. (C) Rats were trained with two consecutive (3-h spaced) weak SOR tasks, using two different pair of identical objects at different position. 24-h later half of the animals were tested for SOR-LTM, changing the position of one object of the pair 1 (Control Pair 1, n = 8) and the rest changing one of the pair 2 (Control Pair 2, n = 7). Exploration time is expressed in percentage of mean ± SEM. P > 0.05, one-way ANOVA. Separate groups were trained as above but 1-h before they were exposed to a novel OF. Again, one group of rats was tested for pair 1 SOR- LTM (OF + Pair 1, n = 7) and the other for pair 2 (OF + Pair 2, n = 7). *, P < 0.05, vs. all groups; Newman-Keuls after one-way ANOVA.