Mora-Gallegos Andrea, Fornaguera Jaime
Neuroscience Research Center, University of Costa Rica, Costa Rica.
Neuroscience Research Center, University of Costa Rica, Costa Rica; Biochemistry Department, Medicine School, University of Costa Rica, Costa Rica.
Behav Processes. 2019 Jan;158:59-69. doi: 10.1016/j.beproc.2018.10.022. Epub 2018 Oct 31.
Animal models of fear and anxiety provide important insight into anxiety-related symptoms in humans. Environmental physical conditions and social contact influence behavior and brain plasticity particularly at early developmental stages and have long lasting effects reaching even adulthood. The potential benefit that a later environmental enrichment may have on rats raised in isolation is however not fully understood. We aim to investigate the effects of housing conditions and their reversion on anxiety and fear-related behaviors in rats. In phase I, we compared the effects of different housing conditions (environmental enrichment, control and social isolation) on anxiety behaviors in the open field test, elevated plus maze and fear conditioning. We found stronger effects of housing on behavioral tests when induced at weaning (phase I), than later in development (phase II). After one month, EE rats showed lower anxiety related behaviors and more freezing in FC. In phase II, we evaluated the effects of the reversion of housing conditions on the same behavioral parameters. We observed a behavioral trend such that the groups started to behave similar to their new housing conditions in OFT mainly. These results suggest that housing conditions at weaning can have long-lasting effects on anxiety and fear-related behaviors. Because the behavioral changes observed after the housing reversal in adulthood were partial, we suggest that more time of social and physical enrichment could be necessary to promote major changes in behavior at this age.
恐惧和焦虑的动物模型为了解人类焦虑相关症状提供了重要的见解。环境物理条件和社会接触会影响行为和大脑可塑性，尤其是在早期发育阶段，并且具有持久影响，甚至会持续到成年期。然而，后期环境丰富化对单独饲养的大鼠可能产生的潜在益处尚未完全了解。我们旨在研究饲养条件及其逆转对大鼠焦虑和恐惧相关行为的影响。在第一阶段，我们比较了不同饲养条件（环境丰富化、对照和社会隔离）在旷场试验、高架十字迷宫和恐惧条件反射中对焦虑行为的影响。我们发现，在断奶时（第一阶段）诱导的饲养条件对行为测试的影响比在发育后期（第二阶段）更强。一个月后，环境丰富化饲养的大鼠在恐惧条件反射中表现出较低的焦虑相关行为和更多的僵住反应。在第二阶段，我们评估了饲养条件逆转对相同行为参数的影响。我们观察到一种行为趋势，即这些组在旷场试验中开始主要表现得与其新的饲养条件相似。这些结果表明，断奶时的饲养条件可能对焦虑和恐惧相关行为产生持久影响。由于成年期饲养条件逆转后观察到的行为变化是部分的，我们认为可能需要更多时间的社会和物理丰富化来促进这个年龄段行为的重大变化。
