Borta Andreas, Schwarting Rainer K W
Experimental and Physiological Psychology, Philipps-University of Marburg, Gutenbergstr. 18, 35032 Marburg, Germany.
Physiol Behav. 2005 Mar 16;84(3):387-96. doi: 10.1016/j.physbeh.2005.01.009.
Substantial work has shown that rats although identical in strain, sex, age and housing conditions can differ considerably in terms of behavior and physiology. Such individual differences can be rather stable and may be detected by behavioral screening tests. Here, the degree of behavioral activation in a novel open-field situation has been shown to serve as a useful predictor to classify animals of a given population into sub-groups with high or low activity, based on measures like locomotion or rearing activity. We used such a screening test and assigned larger samples of male adult Wistar rats into those with high versus low rearing activity (HRA/LRA). They were then tested in the elevated plus-maze, in an inhibitory avoidance task, and in two tests of pain reactivity (hot-plate, tail-flick). In the open field, HRA rats not only showed more rearing behavior, but also more locomotor activity than LRA rats. In the plus-maze, HRA rats again showed more rearing behavior. Also, they spent less time in the open arms, and entered the closed arm more often than low responder rats, which is indicative of more anxiety-related behavior than in LRA rats. In the inhibitory avoidance test, HRA and LRA rats showed similar basal step-in latencies, whereas HRA rats had shorter retention scores than LRA rats after experience of footshock, especially when using a higher (0.5 mA) shock intensity. In contrast, repeated exposure to the avoidance apparatus without shock did not affect step-in latencies in either group. In the pain test, HRA and LRA rats behaved similarly, indicating that their differences in inhibitory avoidance behavior were probably not determined on the level of pain processing. The relevance of these findings is discussed in the context of previous work, especially with respect to the role of processing of aversive experiences.
大量研究表明，尽管大鼠在品系、性别、年龄和饲养条件上相同，但在行为和生理方面可能存在很大差异。这种个体差异可能相当稳定，并且可以通过行为筛选测试检测到。在这里，已经表明在新颖的旷场情境中的行为激活程度可以作为一种有用的预测指标，根据诸如运动或竖毛活动等测量，将给定群体的动物分为高活动或低活动亚组。我们使用了这样一种筛选测试，并将较大样本的成年雄性Wistar大鼠分为高竖毛活动组和低竖毛活动组（HRA/LRA）。然后对它们进行高架十字迷宫测试、抑制性回避任务测试以及两项疼痛反应性测试（热板法、甩尾法）。在旷场中，HRA大鼠不仅表现出更多的竖毛行为，而且比LRA大鼠表现出更多的运动活动。在十字迷宫中，HRA大鼠再次表现出更多的竖毛行为。此外，它们在开放臂中花费的时间更少，并且比低反应大鼠更频繁地进入封闭臂，这表明它们比LRA大鼠有更多与焦虑相关的行为。在抑制性回避测试中，HRA和LRA大鼠表现出相似的基础进入潜伏期，而在经历足部电击后，HRA大鼠的记忆保持得分比LRA大鼠短，特别是当使用较高（0.5 mA）的电击强度时。相比之下，在没有电击的情况下重复暴露于回避装置对两组的进入潜伏期均无影响。在疼痛测试中，HRA和LRA大鼠表现相似，表明它们在抑制性回避行为上的差异可能不是由疼痛处理水平决定的。这些发现的相关性在先前工作的背景下进行了讨论，特别是关于厌恶经历处理的作用。
