Experiencing Novelty in Adolescence and the Influence of Prior Novelty-Related Experiences on Adult Behavioral Outcomes in Wistar Han Rats.

Acquiring new experiences, especially in adolescence, shapes behavioral responses to life's challenges. The absence of novelty-related experiences in laboratory rats raises concerns about their behavioral development and the reproducibility of research. This study examined changes in behavioral responses to novelty from early and late adolescence to adulthood, as well as the long-term effects of prior novelty exposure. To assess maturational differences, seven early adolescent, nine late adolescent, and seven adult male Wistar Han rats were tested once in a behavioral battery consisting of the novel arena, novel object exploration, light/dark box, and elevated plus maze. To evaluate the influence of prior experience, early and late adolescent groups were retested once more in adulthood. Late adolescents showed consistent patterns across spatial tasks, displaying increased anxiety-like behavior and reduced exploratory and risk-assessment activity. Early adolescents exhibited variable behaviors, resembling adult or late adolescent profiles depending on the task. Novelty exposure during adolescence produced subtle long-term effects, including reduced discomfort in mildly aversive environments, while late adolescent experience increased thigmotaxis in adulthood. Overall, adolescent responses to novelty were influenced more by spatial than nonspatial environmental features. These findings highlight stage-specific sensitivity to novelty, the influence of adolescent experience, and the potential reuse of experienced animals.