Department of Psychiatry, Laboratory of Psychiatric Neuroimaging (LIM 21), Faculty of Medicine, University of São Paulo, São Paulo, Brazil.
Núcleo de Apoio à Pesquisa em Neurociência Aplicada (NAPNA), University of São Paulo, São Paulo, Brazil.
J Alzheimers Dis. 2018;62(2):757-771. doi: 10.3233/JAD-161036.
Many cross-sectional voxel-based morphometry (VBM) investigations have shown significant inverse correlations between chronological age and gray matter (GM) volume in several brain regions in healthy humans. However, few VBM studies have documented GM decrements in the healthy elderly with repeated MRI measurements obtained in the same subjects. Also, the extent to which the APOE ɛ4 allele influences longitudinal findings of GM reduction in the healthy elderly is unclear.
Verify whether regional GM changes are associated with significant decrements in cognitive performance taking in account the presence of the APOE ɛ4 allele.
Using structural MRI datasets acquired in 55 cognitively intact elderly subjects at two time-points separated by approximately three years, we searched for voxels showing significant GM reductions taking into account differences in APOE genotype.
We found global GM reductions as well as regional GM decrements in the right thalamus and left parahippocampal gyrus (p < 0.05, family-wise error corrected for multiple comparisons over the whole brain). These findings were not affected by APOE ɛ4.
Irrespective of APOE ɛ4, longitudinal VBM analyses show that the hippocampal region and thalamus are critical sites where GM shrinkage is greater than the degree of global volume reduction in healthy elderly subjects.
许多横断面基于体素的形态计量学（VBM）研究表明，在健康人群的几个大脑区域中，年龄与灰质（GM）体积之间存在显著的负相关。然而，很少有 VBM 研究记录了健康老年人在相同受试者中重复 MRI 测量时的 GM 减少。此外，APOE ɛ4 等位基因对健康老年人 GM 减少的纵向研究结果的影响程度尚不清楚。
验证区域 GM 变化是否与认知表现的显著下降相关，同时考虑到 APOE ɛ4 等位基因的存在。
使用结构 MRI 数据集，在 55 名认知正常的老年人中，在大约三年的两个时间点上采集，我们搜索了显示 GM 减少的体素，同时考虑了 APOE 基因型的差异。
我们发现了全脑 GM 减少以及右侧丘脑和左侧海马旁回的区域 GM 减少（p<0.05，全脑多重比较的家族性错误校正）。这些发现不受 APOE ɛ4 的影响。
无论 APOE ɛ4 如何，纵向 VBM 分析表明，海马区和丘脑是 GM 萎缩程度大于健康老年人全脑体积减少程度的关键部位。
