Neurobiological changes that occur with aging include a reduction in function and volume of the hippocampus. These changes were associated with corresponding memory deficits in navigation tasks. However, navigation can involve different strategies that are dependent on the hippocampus and caudate nucleus. The proportion of people using hippocampus‐dependent spatial strategies decreases across the lifespan. As such, the decrease in spatial strategies, and corresponding increase in caudate nucleus‐dependent response strategies with age, may play a role in the observed neurobiological changes in the hippocampus. Furthermore, we previously showed a negative correlation between grey matter in the hippocampus and caudate nucleus/striatum in mice, young adults, and in individuals diagnosed with Alzheimer's disease. As such, we hypothesized that this negative relationship between the two structures would be present during normal aging. The aim of the current study was to investigate this gap in the literature by studying the relationship between grey matter in the hippocampus and caudate nucleus of the striatum, in relation to each other and to navigation strategies, during healthy aging. Healthy older adults (N = 39) were tested on the Concurrent Spatial Discrimination Learning Task (CSDLT), a virtual radial task that dissociates between spatial and response strategies. A regression of strategies against structural MRIs showed for the first time in older adults that the response strategy was associated with higher amounts of grey matter in the caudate nucleus. As expected, the spatial strategy correlated with grey matter in the hippocampus, which was negatively correlated with grey matter in the caudate nucleus. Interestingly, a sex difference emerged showing that among older adult response learners, women have the least amount of grey matter in the hippocampus, which is a known risk for Alzheimer's disease. This difference was absent among spatial learners. These results are discussed in the context of the putative protective role of spatial memory against grey matter loss in the hippocampus, especially in women.

中文翻译：

---

健康老龄化过程中海马体灰质与尾状核呈负相关。

随着衰老发生的神经生物学变化包括海马体功能和体积的减少。这些变化与导航任务中相应的记忆缺陷有关。然而，导航可能涉及依赖于海马体和尾状核的不同策略。使用依赖海马体的空间策略的人的比例在整个生命周期中都在下降。因此，空间策略的减少以及尾状核依赖性反应策略随着年龄的增长而相应增加，可能在观察到的海马神经生物学变化中起作用。此外，我们之前在小鼠、年轻成人和诊断出患有阿尔茨海默病的个体中显示了海马体灰质与尾状核/纹状体之间的负相关。像这样，我们假设在正常衰老过程中会存在这两种结构之间的这种负面关系。本研究的目的是通过研究健康衰老过程中海马体灰质和纹状体尾状核之间的相互关系以及导航策略之间的关系来调查文献中的这一差距。健康的老年人（N= 39) 在并发空间判别学习任务 (CSDLT) 上进行了测试，这是一项在空间和响应策略之间分离的虚拟径向任务。针对结构 MRI 的策略回归首次在老年人中表明，反应策略与尾状核中较高数量的灰质有关。正如预期的那样，空间策略与海马体中的灰质相关，而海马体中的灰质与尾状核中的灰质呈负相关。有趣的是，出现了性别差异，表明在年龄较大的成人反应学习者中，女性海马体中的灰质含量最少，这是已知的阿尔茨海默病风险。这种差异在空间学习者中是不存在的。