The Irish Longitudinal Study on Ageing (TILDA), Trinity College Dublin, Dublin 2, Ireland.
Department of Medical Gerontology, Trinity College Dublin, Dublin 2, Ireland.
Sci Rep. 2019 Jul 29;9(1):10981. doi: 10.1038/s41598-019-46481-5.
The heterogeneous specialisation of hippocampal subfields across memory functions has been widely shown in animal models. Yet, few in vivo studies in humans have explored correspondence between hippocampal subfield anatomy and memory performance in ageing. Here, we used a well-validated automated MR segmentation protocol to measure hippocampal subfield volumes in 436 non-demented adults aged 50+. We explored relationships between hippocampal subfield volume and verbal episodic memory, as indexed by word list recall at immediate presentation and following delay. In separate multilevel models for each task, we tested linearity and non-linearity of associations between recall performance and subfield volume. Fully-adjusted models revealed that immediate and delayed recall were both associated with cubic fits with respect to volume of subfields CA1, CA2/3, CA4, molecular layer, and granule cell layer of dentate gyrus; moreover, these effects were partly dissociable from quadratic age trends, observed for subiculum, molecular layer, hippocampal tail, and CA1. Furthermore, analyses of semantic fluency data revealed little evidence of robust associations with hippocampal subfield volumes. Our results show that specific hippocampal subfields manifest associations with memory encoding and retrieval performance in non-demented older adults; these effects are partly dissociable from age-related atrophy, and from retrieval of well-consolidated semantic categories.
海马亚区在记忆功能上的异质性专门化在动物模型中得到了广泛的证明。然而，在人类中，很少有体内研究探索了海马亚区解剖结构与衰老过程中记忆表现之间的对应关系。在这里，我们使用一种经过充分验证的自动磁共振分割协议，测量了 436 名年龄在 50 岁以上的非痴呆成年人的海马亚区体积。我们探索了海马亚区体积与言语情景记忆之间的关系，情景记忆通过单词列表在即时呈现和延迟后回忆来衡量。在每个任务的单独多层模型中，我们测试了回忆表现与亚区体积之间关联的线性和非线性。经过充分调整的模型表明，即时和延迟回忆都与 CA1、CA2/3、CA4、分子层和齿状回颗粒细胞层的体积呈三次拟合相关；此外，这些效应部分与观察到的下托、分子层、海马尾部和 CA1 的二次年龄趋势相分离。此外，对语义流畅性数据的分析几乎没有显示出与海马亚区体积有明显关联的证据。我们的结果表明，特定的海马亚区与非痴呆老年人大脑中的记忆编码和检索表现存在关联；这些效应部分与年龄相关的萎缩以及对高度巩固的语义类别的检索分离。
