It has clearly been demonstrated that cognitive stimulation, physical exercise, and social engagement help counteract age-related cognitive decline. However, several important issues remain to be addressed. Given the wide differences in cognitive impairment found among individuals of the same age, identifying the subjects who will benefit most from late-life interventions is one such issue. Environmental Enrichment (EE) is a particularly valuable approach to do this. In this study, aged (21-month-old) rats were assigned to a better (BL) or a worse (WL) learner group (training phase) and to a non-impaired (NI) or an impaired (I) group (probe phase) by their performance on the Morris Water Maze, using the test performances of adult (12-month-old) rats as the cut-offs. The aged rats were retested after a 12-week EE or standard housing (SH) protocol. After 12 weeks, the performances of SH rats had deteriorated, whereas all rats benefited from EE, albeit in different ways. In particular, the animals assigned to the BL and the NI groups prior to EE still performed as well as the adult rats (performance preservation) whereas, critically, the animals assigned to the WL and the I groups before EE showed such improved performances that they reached the level of the adult rats (performance improvement), despite having aged further. EE seems to induce the preservation in BLs and the improvement in WLs of spatial search strategies and the preservation in NIs and the increase in Is of a focused and protract research of the escape point. Our findings suggest that late-life EE prevents spatial learning and memory decline in still cognitively preserved animals and stimulates residual functional reserve in already cognitively compromised animals. Future research should focus on individually tailored stimulation protocols to improve their effect and afford a better understanding of the underlying processes.

清楚地表明，认知刺激，体育锻炼和社交参与有助于抵消与年龄有关的认知能力下降。但是，仍有几个重要问题需要解决。鉴于在同一年龄的个体之间发现的认知障碍差异很大，因此确定将受益于后期干预的受试者最多就是一个这样的问题。环境富集（EE）是实现这一目标的一种特别有价值的方法。在这项研究中，将年龄较大（21个月大）的大鼠分为学习能力较好的（BL）或学习能力较差的（WL）学习者组（训练阶段），将其分为无障碍（NI）或障碍（I）组（探查阶段），以成年（12个月大）大鼠的测试表现作为临界值，以它们在莫里斯水迷宫上的表现为依据。在12周的EE或标准住房（SH）协议之后，对成年大鼠进行了重新测试。12周后，SH大鼠的性能下降，而所有大鼠均从EE中受益，尽管采取了不同的方式。尤其是，在EE之前分配给BL和NI组的动物仍然表现出与成年大鼠一样好的表现（保持性能），但是，至关重要的是，在EE之前分配给WL和I组的动物表现出了如此高的性能，以至于它们尽管年龄进一步增长，但仍达到成年大鼠的水平（性能改善）。EE似乎引起了对逃逸点的集中且长期的研究，而BL的保存以及WL的空间搜索策略的改进和NI的保存以及Is的增加。我们的研究结果表明，晚期EE可以防止仍然认知保留的动物的空间学习和记忆力下降，并刺激已经认知受损的动物的残余功能储备。未来的研究应专注于个性化定制的刺激方案，以改善其效果并更好地理解其潜在过程。