Nicolle Michelle M, Prescott Sonya, Bizon Jennifer L
Department of Molecular Neuroscience, Mayo Graduate School, Mayo Clinic, Jacksonville, Florida 32224, USA.
Learn Mem. 2003 Nov-Dec;10(6):520-4. doi: 10.1101/lm.64803.
The effects of age on cue learning, spatial reference memory, and strategy preference were assessed in B6 x SJL F1 mice by using the Morris water maze. This mouse strain is of particular interest because it is the background strain for a common transgenic model of Alzheimer's disease, the Tg2576 mouse, which develops plaques and other neurobiological markers of pathology beginning at 8 mo and increasing in severity with advanced age. In the current study, 12- and 23-mo-old C57B6 x SJL F1 mice were serially trained in cue and place versions of the Morris water maze task. At the completion of training, mice received a strategy probe test in which place (hidden) and cue (visible) strategies were in competition. Cue and spatial learning ability was maintained between 12 and 23 mo of age; however, on the strategy preference probe test, the 23-mo-old mice exhibited a significant bias toward the selection of a cue strategy. There was no relationship between strategy preference in the probe test and spatial learning ability, but the 23-mo-old mice did exhibit a strong trend toward shorter latencies during visible platform training, possibly reflecting the enhanced function of striatal-based neural systems in aging. These data demonstrate that 23-mo-old C57B6 x SJL F1 mice are capable of effective place learning, but if a place strategy is pitted against the use of a cue strategy, the use of a cue strategy predominates in the aged mice. The strategy preference observed here may reflect an emergence of differential processing in underlying brain circuitry with age in the B6 x SJL F1 mouse strain.
通过使用莫里斯水迷宫，评估了B6 x SJL F1小鼠年龄对线索学习、空间参考记忆和策略偏好的影响。这种小鼠品系特别受关注，因为它是阿尔茨海默病常见转基因模型Tg2576小鼠的背景品系，该模型从8个月大开始出现斑块和其他病理学神经生物学标志物，且随着年龄增长严重程度增加。在本研究中，对12月龄和23月龄的C57B6 x SJL F1小鼠进行了莫里斯水迷宫任务的线索和位置版本的系列训练。训练完成后，小鼠接受了一项策略探测测试，其中位置（隐藏）和线索（可见）策略相互竞争。12月龄和23月龄小鼠的线索和空间学习能力保持不变；然而，在策略偏好探测测试中，23月龄小鼠在选择线索策略方面表现出显著偏向。探测测试中的策略偏好与空间学习能力之间没有关系，但23月龄小鼠在可见平台训练期间确实表现出潜伏期缩短的强烈趋势，这可能反映了衰老过程中基于纹状体的神经系统功能增强。这些数据表明，23月龄的C57B6 x SJL F1小鼠能够进行有效的位置学习，但如果位置策略与线索策略的使用相竞争，线索策略在老年小鼠中占主导地位。这里观察到的策略偏好可能反映了B6 x SJL F1小鼠品系中随着年龄增长潜在脑回路中差异处理的出现。
