Masini C V, Sauer S, White J, Day H E W, Campeau S
Department of Psychology and Center for Neuroscience, Muenzinger Bldg, Room D140G, 345 UCB, University of Colorado, Boulder, CO 80309-034, USA.
Physiol Behav. 2006 Jan 30;87(1):72-81. doi: 10.1016/j.physbeh.2005.08.044. Epub 2005 Sep 23.
Predators and their odors offer an ethologically valid model to study learning processes. The present series of experiments assessed the ability of ferret odor to serve as an unconditioned stimulus and examined behavioral and endocrine changes in male Sprague-Dawley rats with single or repeated exposures in a defensive withdrawal paradigm or in their home cages. Rats exposed to ferret odor avoided the ferret odor stimulus more, exhibited greater risk assessment and displayed higher adrenocorticotropin hormone (ACTH) and corticosterone release compared with control odor exposed rats and these measures did not significantly habituate over repeated exposures. Ferret odor exposure did not show associative conditioning effects during extinction trials. However, rats that were pre-exposed to ferret odor only once, as compared to control and repeatedly exposed rats, displayed a sensitized ACTH and corticosterone response to an additional ferret odor exposure in small cages. These experiments suggest that ferret odor is a highly potent unconditioned stimulus that has long lasting effects on behavior and endocrine responses, and further suggests the independence of habituation and sensitization processes.
捕食者及其气味为研究学习过程提供了一个符合行为学原理的有效模型。本系列实验评估了雪貂气味作为一种非条件刺激的能力，并在防御性退缩范式或其笼舍中，对单次或重复暴露于雪貂气味的雄性斯普拉格-道利大鼠的行为和内分泌变化进行了研究。与暴露于对照气味的大鼠相比，暴露于雪貂气味的大鼠对雪貂气味刺激的回避更多，表现出更强的风险评估能力，促肾上腺皮质激素（ACTH）和皮质酮释放水平更高，并且这些指标在重复暴露过程中并未显著习惯化。在消退试验中，雪貂气味暴露未显示出联想性条件作用效应。然而，与对照大鼠和重复暴露的大鼠相比，仅预先暴露于雪貂气味一次的大鼠，在小笼子中再次暴露于雪貂气味时，ACTH和皮质酮反应出现了敏化。这些实验表明，雪貂气味是一种高效的非条件刺激，对行为和内分泌反应具有持久影响，进一步表明习惯化和敏化过程是相互独立的。
