Department of Neuroscience, McKnight Brain Institute, University of Florida Gainesville, FL, USA.
Front Aging Neurosci. 2014 Jan 21;6:2. doi: 10.3389/fnagi.2014.00002. eCollection 2014.
The spatial water maze is routinely used to investigate hippocampal-dependent spatial memory and the biological mechanisms that underlie variability in cognitive decline during aging. The utility of the task for repeated testing in order to examine the trajectory of cognitive decline and to prescreen animals prior to therapeutic interventions maybe limited due to carryover effects of repeated training. The current study examines the role of carryover effects, as well as the reliability of individual differences, in determining age-related impairment on episodic and reference memory versions of the water maze task. Results indicate that impaired acquisition of episodic spatial information emerges in middle-age and the propensity for impairment increases with advancing age. While learning was variable across animals, acquisition deficits for episodic information were reliable across training sessions in middle-age and aged rats. A significant impairment in the 24h retention of episodic spatial information was observed in aged animals. When animals were trained to the same location (i.e., reference memory), an impairment was limited to the rate of acquisition in aged animals. However, with continued training, all aged animals were able to acquire a reference memory and no age differences were observed in the 24h retention of a spatial reference memory. Together, the results point to a progressive impairment in episodic spatial memory with advancing age and suggest that tests of episodic spatial memory are reliable and more sensitive than reference memory for detecting cognitive decline.
空间水迷宫通常用于研究海马依赖性空间记忆，以及衰老过程中认知能力下降的生物学机制。由于重复训练的迁移效应，该任务可能会限制其用于重复测试以检查认知下降轨迹并在治疗干预之前对动物进行预筛选的效用。本研究探讨了迁移效应的作用，以及个体差异的可靠性，以确定在水迷宫任务的情节和参考记忆版本中与年龄相关的损伤。结果表明，情节空间信息的获取受损出现在中年，并且随着年龄的增长，受损的倾向增加。虽然学习在动物之间存在差异，但在中年和老年大鼠中，情节信息的获取缺陷在整个训练过程中都是可靠的。在老年动物中观察到情节空间信息的 24 小时保留显著受损。当动物被训练到相同的位置（即参考记忆）时，仅在老年动物中观察到获取率受损。然而，随着持续训练，所有老年动物都能够获得参考记忆，并且在 24 小时保留空间参考记忆方面没有年龄差异。总之，结果表明随着年龄的增长，情节空间记忆逐渐受损，并且表明情节空间记忆测试比参考记忆更可靠，更敏感，可用于检测认知能力下降。
