Gouirand Angela M, Matuszewich Leslie
Department of Psychology, Northern Illinois University, DeKalb, 60115, USA.
Physiol Behav. 2005 Sep 15;86(1-2):21-31. doi: 10.1016/j.physbeh.2005.06.027.
Exposure to chronic stress can affect cognitive processes in a complex manner depending upon the intensity and duration of the stressors. The current study investigated the effects of chronic unpredictable stress (CUS), a procedure thought to use moderate stressors, on acquisition of and performance in the Morris Water Maze (MWM). Separate behavioral tests were also used to determine whether the stress-induced changes in MWM were due to general changes in locomotor activity or preference for a rewarding stimulus. Adult male rats were exposed to 10 days of different stressors applied at various times. Following the last stressor, stressed and non-stressed rats began training in the MWM, were tested in an open field box, or were tested for sucrose preference. In the MWM, rats exposed to stress had shorter latencies to reach the hidden platform during training. The path lengths on day 2 of training, trials 2 and 4, were shorter in CUS rats compared to controls, with the stressed rats traveling less in the outer portion of the maze. During the probe trial, CUS rats also traveled less overall and less in the outer portion of the maze, although all other measures were the same. The facilitation in learning the platform location was not due to a change in other behavioral components that could contribute to the measures, such as general activity, sensorimotor processing or the preference for a 2% sucrose solution. Thus, chronic unpredictable stress selectively appears to affect the search strategies in the water maze.
长期暴露于慢性应激会以复杂的方式影响认知过程，这取决于应激源的强度和持续时间。本研究调查了慢性不可预测应激（CUS）对莫里斯水迷宫（MWM）学习和表现的影响，CUS是一种使用中等强度应激源的程序。还使用了单独的行为测试来确定MWM中应激诱导的变化是否是由于运动活动的总体变化或对奖励刺激的偏好。成年雄性大鼠在不同时间接受10天的不同应激源处理。在最后一次应激源处理后，应激组和非应激组大鼠开始在MWM中训练，在旷场箱中进行测试，或进行蔗糖偏好测试。在MWM中，接受应激处理的大鼠在训练期间到达隐藏平台的潜伏期较短。与对照组相比，CUS组大鼠在训练第2天的第2次和第4次试验中的路径长度较短，应激组大鼠在迷宫外部的移动较少。在探索试验中，CUS组大鼠在迷宫中的总体移动也较少，在迷宫外部的移动也较少，尽管所有其他测量结果相同。学习平台位置的促进作用并非由于其他可能影响测量结果的行为成分的变化，如总体活动、感觉运动处理或对2%蔗糖溶液的偏好。因此，慢性不可预测应激似乎选择性地影响水迷宫中的搜索策略。
