Sexual Dimorphism in Learning and Memory: A Zebrafish Model Using Fear Conditioning

The zebrafish (Danio rerio) is increasingly utilized as a powerful animal model in investigating learning and memory. While mounting evidence indicates subtle differences in the behaviour of male and female fish in specific aspects, the behaviour of zebrafish from different sexes in avoidance learning and memory that involved red LEDs as the conditioned stimulus has not been investigated. Here, we utilised a Ti-maze behavioural task to assess the role of sex in the learning and memory abilities of adult wild-type zebrafish. The fish were taught to associate red LED lights with electric shocks and swim into the goal arm. As revealed by the frequency of fish entering the wrong arm in the learning phase, our results showed that females outperformed males in learning task. Surprisingly, females showed an increased latency time to enter the goal arm, indicating poorer memory performance which could be related to anxiety in the testing phase. Overall, our results demonstrated the effect of sex on learning and memory analyses. Thus, sex differences should be an important factor to consider in zebrafish model.