Schematic time line of the procedure for the acquisition and retrieval of object location memory (OLM). The data show the effect of treatment with standardized extract of Ginkgo biloba (EGb) or vehicle immediately after the weak encoding session associated or not with contextual novelty (30 min after training) in short-term memory (STM) and long-term memory (LTM) sessions. In the training session, young adult rats were allowed to freely explore the sample objects (A and B) for 5 min (weak training [WT]), and the mean discrimination index (DI) and recognition index (RI) of the sample objects were evaluated in independent cohorts of rats subjected to STM or LTM (n = 7-–8 per group/time probe test). The DI (A,C) and RI (B,D) of the moved and sample objects were evaluated for 5 min in the object location memory testing (OLM) 1 h after training (STM) (A,B) or 24 h after training (LTM) (C,D) in rats of the WT, WT + EGb, WT + vehicle + novelty, and WT + EGb + novelty groups (n = 7–8 per group/time probe test). All individual values are shown. The values are presented as the means (±SEMs). Lines represent the chance value for the DI (0.0) and RI (0.5). Comparisons between the ratio discriminations from the group above chance level used one-sample t-tests. Intragroup comparisons (testing vs. training sessions) used a paired t-test and revealed the effect of novelty and/or EGb on LTM.
