Fig. 1: Females show a similar STM capacity to males, but greater resistance to retroactive interference at the expense of reduced memory consolidation.

a–d Bar charts report exploration of the new object (circled) and each of the familiar ones (F) in the Different/Identical Object Task (DOT-IOT). Female mice explored significantly more the new object compared to all the familiar ones at 1 min delay in all the control tasks (IOTs) and in the 3-DOT (a, low load), 4-DOT (b, intermediate load), and 6-DOT (c, high load), but not in the 9-DOT (d, overload). e–h In the LTM tasks, females explored significantly more the new object compared to all the familiar ones at 24 h delay in the 3-DOT (e) and 4-DOT (f), but they showed an impaired performance in the 6-DOT (g), already at 1 h delay (h). *p < 0.05 New vs all the familiar objects (one-way repeated measure ANOVA followed by Dunnett post-hoc). i–i′ Schematic of the task to test the effect of retroactive interference on memory capacity at 1 min delay (i). No effect of the interference protocol was found on the performance of males and females in the 6-IOT (i′). However, while interference caused a significant decrease of the new % exploration in males, no effect was revealed in females (i′), which demonstrated to be resistant to retroactive interference even in high memory load condition. *p < 0.05 control vs interference within sex (one-way ANOVA). Data in bar charts are presented as mean values ± SEM. For statistics see Supplementary Table 5.