Winocur Gordon, Moscovitch Morris, Caruana Douglas A, Binns Malcolm A
Department of Psychology, Trent University, Ontario, Canada.
Neuropsychologia. 2005;43(11):1580-90. doi: 10.1016/j.neuropsychologia.2005.01.013. Epub 2005 Feb 23.
The present study examined remote spatial memory in a test that spans several months to determine whether remote memories are spared relative to more recent ones, as predicted by models of memory consolidation. At 3, 6 or 12 months of age, groups of rats received forced-choice training as to the location of food reward in a cross maze. At 12.5 months, rats received bilateral neurotoxic lesions to the hippocampus or a control surgical procedure and 2 weeks later their memory for the spatial location was tested. Their performance was compared to that of rats with hippocampal or control lesions with no prior training on several measures of savings. The hippocampal group with no pre-training, as expected, was severely impaired in learning the location of the food reward. Compared to this group, rats with hippocampal lesions that were pre-trained consistently performed better at the shortest training-surgery interval but not at the longer ones. That is, rats with hippocampal lesions exhibited retrograde amnesia at all training-surgery intervals and a forgetting curve that paralleled that of the control groups. The results were interpreted within a framework that distinguishes between relational and associative context, and as providing evidence that the hippocampus is necessary for the retention and retrieval of memories that are bound to relational context, regardless of the age of the memory.
本研究在一项持续数月的测试中考察了远期空间记忆，以确定远期记忆是否如记忆巩固模型所预测的那样，相对于近期记忆而言得以保留。在3、6或12月龄时，将几组大鼠置于十字迷宫中进行食物奖励位置的强制选择训练。在12.5月龄时，大鼠接受双侧海马神经毒性损伤或对照手术操作，两周后测试它们对空间位置的记忆。在几种节省量测量指标上，将它们的表现与未接受过先前训练的海马损伤或对照损伤大鼠的表现进行比较。正如预期的那样，未接受过预训练的海马组在学习食物奖励位置方面严重受损。与该组相比，接受过预训练的海马损伤大鼠在最短训练-手术间隔时表现始终更好，但在较长间隔时则不然。也就是说，海马损伤大鼠在所有训练-手术间隔时均表现出逆行性遗忘，且遗忘曲线与对照组平行。研究结果是在一个区分关系性和关联性情境的框架内进行解释的，并且被视为提供了证据，表明海马对于与关系性情境相关的记忆的保持和提取是必要的，而与记忆的年龄无关。
