There is evidence for a hippocampal long axis anterior–posterior (AP) differentiation in memory processing, which may have implications for the changes in episodic memory performance seen across development and aging. The hippocampus shows substantial structural changes with age, but the lifespan trajectories of hippocampal sub‐regions along the AP axis are not established. The aim of the present study was to test whether the micro‐ and macro‐structural age‐trajectories of the anterior (aHC) and posterior (pHC) hippocampus are different. In a single‐center longitudinal study, 1,790 cognitively healthy participants, 4.1–93.4 years of age, underwent a total of 3,367 MRI examinations and 3,033 memory tests sessions over 1–6 time points, spanning an interval up to 11.1 years. T1‐weighted scans were used to estimate the volume of aHC and pHC (macrostructure), and diffusion tensor imaging to measure mean diffusion (MD, microstructure) within each region. We found that the macro‐ and microstructural lifespan‐trajectories of aHC and pHC were clearly distinguishable, with partly common and partly unique variance shared with age. aHC showed a protracted period of microstructural development, while pHC microstructural development as indexed by MD was more or less completed in early childhood. In contrast, pHC showed larger unique aging‐related changes. An aHC–pHC difference was also observed for volume, with pHC changing relatively more with higher age. All regions showed age‐dependent relationships with episodic memory. aHC micro‐ and macrostructure was significantly related to verbal memory independently of age, but the relationships were still strongest among the older participants. We suggest that memory processes supported by each sub‐region improve or decline in concert with volumetric and microstructural changes in the same age‐period. Future research should disentangle the lifespan relationship between changes in these structural properties and different memory processes, encoding versus retrieval in particular, as well as other cognitive functions depending on the hippocampal long‐axis specialization.

中文翻译：

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整个生命周期中与记忆相关的前海马体和后海马体宏观和微观结构——一项纵向研究。

有证据表明，海马长轴前后 (AP) 在记忆处理中存在分化，这可能对整个发育和衰老过程中情景记忆表现的变化产生影响。海马体随着年龄的增长显示出显着的结构变化，但沿 AP 轴的海马体亚区的寿命轨迹尚未确定。本研究的目的是测试前海马体 (aHC) 和后海马体 (pHC) 的微观和宏观结构年龄轨迹是否不同。在一项单中心纵向研究中，1,790 名年龄在 4.1-93.4 岁之间的认知健康参与者在 1-6 个时间点共接受了 3,367 次 MRI 检查和 3,033 次记忆测试，时间间隔长达 11.1 年。T1 加权扫描用于估计 aHC 和 pHC（宏观结构）的体积，并使用扩散张量成像来测量每个区域内的平均扩散（MD，微观结构）。我们发现 aHC 和 pHC 的宏观和微观结构寿命轨迹是明显可区分的，部分常见和部分独特的差异与年龄共享。aHC 显示出长期的微观结构发育，而 MD 所指示的 pHC 微观结构发育或多或少在儿童早期完成。相比之下，pHC 表现出更大的独特的衰老相关变化。体积也观察到 aHC-pHC 的差异，随着年龄的增长，pHC 的变化相对更大。所有区域都显示出与情景记忆的年龄相关关系。aHC 微观和宏观结构与年龄无关的言语记忆显着相关，但年龄较大的参与者之间的关系仍然最强。我们建议每个子区域支持的记忆过程随着体积和微观结构的变化而改善或下降。未来的研究应该理清这些结构特性的变化与不同记忆过程之间的寿命关系，特别是编码与检索，以及取决于海马长轴专业化的其他认知功能。