Burnell Hannah G, Blocker Beckett R J, Meyer Heidi C
Department of Psychological and Brain Sciences, Boston University, Boston, Massachusetts, USA.
Center for Systems Neuroscience, Boston University, Boston, Massachusetts, USA.
Dev Psychobiol. 2025 Mar;67(2):e70038. doi: 10.1002/dev.70038.
Previous research has sought to understand the mechanisms by which early life adversity disrupts later behavioral function. Yet less has been done to investigate the effects of positive experiences such as environmental enrichment. Here, we examined the effects of brief (2 weeks) or extended (8 weeks) environmental enrichment on discrimination, fear inhibition, and fear extinction during adolescence or adulthood. Two conditions of enrichment were used: a "Hut" group received a polycarbonate Hut in the home cage throughout the duration of the experiment, while a "Variable" group received a polycarbonate Hut, as well as a series of rotating enrichment features. Our data show that in females, brief Variable enrichment increased the rate of learning about cues that explicitly indicate safety during adolescence while disrupting this type of learning in adults. In males, enrichment did not influence learning about safety cues. Conversely, in males, brief Variable enrichment initially improved extinction, but extended enrichment (Variable or Hut) was necessary to see sustained improvements across extinction. This pattern was apparent for both adolescents and adults. In females, Variable enrichment did not affect extinction, while Hut enrichment increased freezing for all mice initially and adolescents as extinction continued. This work has the potential to inform treatments and interventions for fear-related disorders, such as anxiety and post-traumatic stress disorder, tailored for both specific developmental ages and sex.
先前的研究试图了解早期生活逆境破坏后期行为功能的机制。然而，对于诸如环境丰富化等积极经历的影响，所做的研究较少。在此，我们研究了短期（2周）或长期（8周）环境丰富化对青春期或成年期辨别、恐惧抑制和恐惧消退的影响。使用了两种丰富化条件：“小屋”组在整个实验期间在家笼中放置一个聚碳酸酯小屋，而“可变”组除了一个聚碳酸酯小屋外，还配备一系列可旋转的丰富化设施。我们的数据表明，在雌性中，短期可变丰富化提高了青春期学习明确指示安全线索的速率，同时却干扰了成年期的此类学习。在雄性中，丰富化并未影响对安全线索的学习。相反，在雄性中，短期可变丰富化最初改善了消退，但需要长期丰富化（可变或小屋条件）才能在整个消退过程中看到持续改善。这种模式在青少年和成年人中都很明显。在雌性中，可变丰富化不影响消退，而小屋丰富化最初使所有小鼠的僵立增加，并且随着消退的持续，青少年小鼠的僵立也增加。这项工作有可能为针对特定发育年龄和性别的恐惧相关障碍（如焦虑症和创伤后应激障碍）的治疗和干预提供依据。
