Luparini M R, Del Vecchio A, Barillari G, Magnani M, Prosdocimi M
ACRAF Angelini Ricerche, S. Palomba Pomezia, Roma, Italy.
Aging (Milano). 2000 Aug;12(4):264-73. doi: 10.1007/BF03339846.
The behavioral performance of young and aged rats was studied in a repeated-trials test. Young animals reacted to both spatial displacement and novelty, whereas most aged rats lost the ability to react to novelty although maintaining spatial memory. The cluster analysis procedure performed on all the tested subjects enabled the recognition of a consistent group of the aged sample (35%) with a mild degree of spatial and non-spatial memory impairment. Spatial memory impairment of some of the aged animals was also evaluated in the Morris water maze test. On the fifth day of the task, we observed a very low percentage of impaired aged animals, which partially corresponded to the impaired group identified by the object recognition test. In contrast, the subgroup of mildly impaired rats performed similarly to the young animals. We advance that the Morris water maze might represent a stressful experimental condition for aged rats, enhancing the motivational level of animals subjected to this procedure. This condition may alter the cognitive responses. As a consequence, the "mildly impaired" rats, which may be considered an interesting group for investigating memory-enhancing drugs, will infrequently be recognized with the Morris water maze test. Cognitive impairment in aged rats should be studied utilizing a sensitive test in which motivation does not substantially influence the results of the test.
在重复试验测试中研究了年轻和老年大鼠的行为表现。年轻动物对空间位移和新奇事物均有反应，而大多数老年大鼠虽然保持空间记忆，但失去了对新奇事物的反应能力。对所有受试对象进行的聚类分析程序能够识别出老年样本中一组一致的群体（35%），其存在轻度的空间和非空间记忆损伤。还在莫里斯水迷宫测试中评估了一些老年动物的空间记忆损伤情况。在任务的第五天，我们观察到受损老年动物的比例非常低，这部分与通过物体识别测试确定的受损组相对应。相比之下，轻度受损大鼠亚组的表现与年轻动物相似。我们提出，莫里斯水迷宫可能对老年大鼠来说是一种有压力的实验条件，会提高接受该程序动物的动机水平。这种情况可能会改变认知反应。因此，“轻度受损”大鼠（可能被认为是研究记忆增强药物的一个有趣群体）在莫里斯水迷宫测试中很少会被识别出来。应该利用一种敏感的测试来研究老年大鼠的认知损伤，在这种测试中动机不会对测试结果产生实质性影响。
