Dunnett S B, Evenden J L, Iversen S D
Department of Experimental Psychology, University of Cambridge, UK.
Psychopharmacology (Berl). 1988;96(2):174-80. doi: 10.1007/BF00177557.
Separate groups of rats of three ages (6 month, 15 month or 24 month) were trained in a two-lever operant chamber on one of two versions of a paired-trial delayed response task involving either matching or non-matching of the choice response to a sample lever. The older rats were unimpaired in learning either version of the task during initial training with no (0 s) delay between the sample and choice responses. However, when variable 0-24 s delay intervals were introduced, the 24-month group was impaired on acquisition of the delayed non-matching task, and both the 15- and 24-month groups were impaired on acquisition of the delayed matching task compared to the 6-month group. Deficits in the older groups in asymptotic performance were attributable to an impairment at longer delay intervals whilst maintaining near perfect performance at the shorter delay intervals, suggesting a selective short-term memory impairment. The delay-dependent deficits of the older groups were not ameliorated by the muscarinic agonist arecoline or the cholinesterase inhibitor physostigmine, and so failed to corroborate a cholinergic interpretation of the observed age-related impairment in short-term memory.
将三组不同年龄（6个月、15个月或24个月）的大鼠分别置于双杠杆操作箱中，在涉及对样本杠杆的选择反应进行匹配或不匹配的两种配对试验延迟反应任务版本之一上进行训练。在样本反应和选择反应之间无延迟（0秒）的初始训练期间，老年大鼠学习这两种任务版本均未受损。然而，当引入0至24秒的可变延迟间隔时，与6个月龄组相比，24个月龄组在延迟不匹配任务的习得方面受损，15个月龄组和24个月龄组在延迟匹配任务的习得方面均受损。老年组渐近表现的缺陷归因于在较长延迟间隔时的损伤，而在较短延迟间隔时保持近乎完美的表现，这表明存在选择性短期记忆损伤。老年组与延迟相关的缺陷并未因毒蕈碱激动剂槟榔碱或胆碱酯酶抑制剂毒扁豆碱而改善，因此未能证实对观察到的与年龄相关的短期记忆损伤的胆碱能解释。
