Spatial memory tasks in aged animals: Overcoming methodological challenges

Memory declines in healthy aging, although deficits are heterogeneous. Implicit, procedural, and semantic memory, for example, are relatively preserved, whereas spatial abilities are particularly vulnerable. This vulnerability may reflect changes in the mechanisms underlying spatial navigation. Older adults tend to show impairments in allocentric processing, which encodes object-to-object relationships and environmental features, while relying more on egocentric, route-based strategies. Rodent studies are essential for investigating these changes. However, standard behavioral paradigms developed for young or adult animals may yield misleading or non-translatable results if applied without adaptation to aged mice and rats. This review focuses on four spatial memory tasks: the Morris water maze, the Barnes maze, the object location, and the spontaneous location recognition. These tests primarily rely on allocentric strategies and are sensitive to age-related alterations in the hippocampal-entorhinal cortex, the neural substrate for forming allocentric cognitive maps. The review highlights age-related characteristics, such as reduced physical fitness, sensory decline, and hormonal alterations, that require specific adjustments to experimental protocols, and outlines methodological considerations for adapting procedures, selecting additional assessments, and applying scoring systems in an unbiased manner. An exploratory survey of the literature is also presented to assess how frequently such adaptations are reported. Overall, the synthesis underscores the importance of methodological refinement for improving the validity and translational relevance of aging research.