Zimmermann A, Stauffacher M, Langhans W, Würbel H
Institut für Nutztierwissenschaften, Physiologie und Tierhaltung, ETH Zürich, Schorenstrasse 16, 8603 Schwerzenbach, Switzerland.
Behav Brain Res. 2001 Jun;121(1-2):11-20. doi: 10.1016/s0166-4328(00)00377-6.
In rats, exploratory activity and emotional reactivity towards novel stimuli reflect independent biological functions that are modulated differently by rearing experiences. Environmental enrichment is known to improve performance in exploratory tasks, while having inconsistent effects on emotionality. This study examined the effect of environmental enrichment on the behaviour of rats in two exploratory tasks. Male rats were reared under one of four conditions, differing in social and non-social complexity. At 9 weeks of age, exploration of a novel open field, and exploration of novel objects in the same open field following 24 h habituation, was assessed. Differences in social and non-social complexity of the rearing environment had inconsistent effects on exploration in the novel open field. In contrast, when rats were faced with novel objects in an otherwise familiar environment, exploration habituated faster with increasing stimulus complexity of the non-social environment. The social environment had no effect on this latter test. These findings indicate that environmental enrichment affects exploratory activity primarily through its effect on habituation to novelty. This effect depends on relative stimulus complexity of the rearing environment, but is independent of social factors. The present results further suggest that aversive tasks can obscure the expression of enrichment-dependent differences in habituation to novelty.
在大鼠中，对新刺激的探索活动和情绪反应反映了独立的生物学功能，这些功能受饲养经历的调节方式不同。已知环境丰富化可改善探索任务中的表现，但对情绪的影响并不一致。本研究考察了环境丰富化对大鼠在两项探索任务中行为的影响。雄性大鼠在四种条件之一的环境下饲养，这些条件在社会和非社会复杂性方面存在差异。在9周龄时，评估大鼠对新开放场地的探索，以及在24小时适应期后在同一开放场地对新物体的探索。饲养环境的社会和非社会复杂性差异对在新开放场地中的探索产生的影响并不一致。相比之下，当大鼠在其他方面熟悉的环境中面对新物体时，随着非社会环境刺激复杂性的增加，探索习惯化的速度更快。社会环境对后一项测试没有影响。这些发现表明，环境丰富化主要通过其对新奇事物习惯化的影响来影响探索活动。这种影响取决于饲养环境的相对刺激复杂性，但与社会因素无关。目前的结果进一步表明，厌恶任务可能会掩盖与丰富化相关的新奇事物习惯化差异的表现。
