Prior studies have suggested that short periods of exposure to environmental enrichment (EE) in rodents induce physiological and behavioral effects. In the present study, our aim was to evaluate if the impact of experiences based on EE could be modulated by the age of onset and the developmental period of exposure. NMRI male mice (n = 64) were exposed to EE or standard environment (SE) and behavioral changes (anxiety, exploration, memory and social interaction) were evaluated. Groups compared were: (a) SE: exposure to SE on post-natal day (PND) 28 and lasting 6 months; (b) EE-6: exposure to EE on PND 28 and lasting 6 months; (c) EE-4: exposure to EE on PND 91 and lasting 4 months; (d) EE-2: exposure to EE on PND 154 and lasting 2 months. Results indicated that in the hole-board task the decrease in exploratory behavior reached significance when EE was initiated at adolescence whereas anxiolytic effects in the elevated plus-maze tend to diminish after a longer period of EE. No significant effects of EE on aggressive behavior or novel object recognition were obtained. Taking these results into account, further studies are needed in order to determine the possible modulating role of age and duration of exposure to enriched environments on behavior. Results obtained could explain some discrepancies reported in previous studies, providing new evidence that could contribute to the design of future research related to the benefits of complex and enriched environments.

中文翻译：

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基于环境丰富的经验对行为的影响：雄性 NMRI 小鼠年龄和暴露时间的影响

先前的研究表明，啮齿动物短期暴露于环境富集（EE）会引起生理和行为影响。在本研究中，我们的目的是评估基于 EE 的经验的影响是否可以通过发病年龄和暴露的发育期来调节。NMRI 雄性小鼠 ( n = 64) 暴露于 EE 或标准环境 (SE) 并评估行为变化（焦虑、探索、记忆和社交互动）。比较的组是： (a) SE：在产后第 28 天 (PND) 暴露于 SE 并持续 6 个月；(b) EE-6：在 PND 28 时接触 EE，持续 6 个月；(c) EE-4：在 PND 91 时接触 EE，持续 4 个月；(d) EE-2：在 PND 154 时接触 EE，持续 2 个月。结果表明，在孔板任务中，当 EE 在青春期开始时，探索行为的减少达到显着性，而在高架十字迷宫中的抗焦虑作用在较长时间的 EE 后趋于减弱。EE 对攻击性行为或新物体识别没有显着影响。考虑到这些结果，需要进一步研究以确定年龄和暴露于丰富环境的持续时间对行为的可能调节作用。获得的结果可以解释以前研究中报告的一些差异，提供新的证据，有助于设计与复杂和丰富环境的益处相关的未来研究。