University of Texas at Austin, Austin, TX, USA.
University of California San Diego, San Diego, CA, USA.
BMC Neurosci. 2024 Oct 25;25(1):55. doi: 10.1186/s12868-024-00905-9.
Research has increasingly recognized sex differences in aging and Alzheimer's Disease (AD) susceptibility. However, sex effects on the medial temporal lobe (MTL), a crucial region affected by aging and AD, remain poorly understood when it comes to the intricacies of morphology and functional connectivity. This study aimed to systematically analyze structural and functional connectivity among MTL subregions, which are known to exhibit documented morphological sex differences, during midlife, occurring before the putative pivotal age of cerebral decline. The study sought to explore the hypothesis that these differences in MTL subregion volumes would manifest in sex-related functional distinctions within the broader brain network.
201 cognitively unimpaired adults were included and stratified into four groups according to age and sex (i.e., Women and Men aged 40-50 and 50-60). These participants underwent comprehensive high-resolution structural MRI as well as resting-state functional MRI (rsfMRI). Utilizing established automated segmentation, we delineated MTL subregions and assessed morphological differences through an ANOVA. Subsequently, the CONN toolbox was employed for conducting ROI-to-ROI and Fractional Amplitude of Low-Frequency Fluctuations (fALFF) analyses to investigate functional connectivity within the specific MTL subregions among these distinct groups.
Significant differences in volumetric measurements were found primarily between women aged 40-50 and men of all ages, in the posterior hippocampus (pHPC) and the parahippocampal (PHC) cortex (p < 0.001), and, to a lesser extent, between women aged 50-60 and men of all ages (p < 0.05). Other distinctions were observed, but no significant differences in connectivity patterns or fALFF scores were detected between these groups.
Despite notable sex-related morphological differences in the posterior HPC and PHC regions, women and men appear to share a common pattern of brain connectivity at midlife. Longitudinal analyses are necessary to assess if midlife morphological sex differences in the MTL produce functional changes over time and thus, their potential role in cerebral decline.
Not applicable.
研究越来越多地认识到衰老和阿尔茨海默病（AD）易感性的性别差异。然而，当涉及到形态和功能连接的复杂性时，关于内侧颞叶（MTL）的性别影响，这是一个受衰老和 AD 影响的关键区域，仍然知之甚少。本研究旨在系统地分析 MTL 亚区的结构和功能连接，这些亚区已知在形态上存在性别差异，并且发生在大脑衰退的关键年龄之前的中年时期。该研究旨在探索这样一个假设，即这些 MTL 亚区体积的差异将表现在更广泛的大脑网络内的与性别相关的功能差异中。
共纳入 201 名认知正常的成年人，并根据年龄和性别分为四组（即 40-50 岁和 50-60 岁的女性和男性）。这些参与者接受了全面的高分辨率结构 MRI 和静息状态功能 MRI（rsfMRI）。我们使用已建立的自动分割方法，描绘了 MTL 亚区，并通过 ANOVA 评估了形态差异。随后，使用 CONN 工具箱进行 ROI-ROI 和低频振幅（fALFF）分析，以研究这些不同组之间特定 MTL 亚区的功能连接。
主要在 40-50 岁的女性和所有年龄段的男性之间，在后海马（pHPC）和海马旁皮质（PHC）（p<0.001），以及在较小程度上，在 50-60 岁的女性和所有年龄段的男性之间（p<0.05）发现了体积测量的显著差异。在这些组之间还观察到了其他差异，但没有发现连接模式或 fALFF 分数的显著差异。
尽管在后 HPC 和 PHC 区域存在明显的与性别相关的形态差异，但女性和男性在中年时似乎具有共同的大脑连接模式。需要进行纵向分析，以评估 MTL 的中年形态性别差异是否会随着时间的推移产生功能变化，从而在大脑衰退中发挥潜在作用。
不适用。
