Nazlee Nafeesa, Waiter Gordon D, Sandu Anca-Larisa
Aberdeen Biomedical Imaging Centre, University of Aberdeen, Aberdeen, Scotland.
Hum Brain Mapp. 2023 Jan;44(1):49-65. doi: 10.1002/hbm.26076. Epub 2022 Sep 15.
Cortical morphology changes with ageing and age-related neurodegenerative diseases. Previous studies suggest that the age effect is more pronounced in the frontal lobe. However, our knowledge of structural complexity changes in male and female brains is still limited. We measured cortical ribbon complexity through fractal dimension (FD) analysis at the hemisphere and lobe level in 7010 individuals from the UK Biobank imaging cohort to study age-related sex differences (3332 males, age ranged 45-79 years). FD decreases significantly with age and sexual dimorphism exists. With correction for brain size, females showed higher complexity in the left hemisphere and left and right parietal lobes whereas males showed higher complexity in the right temporal and left and right occipital lobes. A nonlinear age effect was observed in the left and right frontal, and right temporal lobes. Differential patterns of age effects were observed in both sexes with relatively more age-affected regions in males. Significantly higher rightward asymmetries at hemisphere, frontal, parietal, and occipital lobe level and higher leftward asymmetry in temporal lobe were observed. There was no age-by-sex-by asymmetry interaction in any region. When controlling for brain size, the leftward hemispheric, and temporal lobe asymmetry decreased with age. Males had significantly lower asymmetry between hemispheres and higher asymmetry in the parietal and occipital lobes than females. This work provides distinct patterns of age-related sex and asymmetry differences that can aid in the future development of sex-specific models of the normal brain to ascribe cognitive functional significance of these patterns in ageing.
皮质形态会随着年龄增长和与年龄相关的神经退行性疾病而发生变化。先前的研究表明，年龄效应在额叶更为明显。然而，我们对男性和女性大脑结构复杂性变化的了解仍然有限。我们通过分形维数（FD）分析，对英国生物银行成像队列中的7010名个体（3332名男性，年龄在45-79岁之间）的半球和脑叶水平的皮质带复杂性进行了测量，以研究与年龄相关的性别差异。FD随年龄显著降低，且存在性别二态性。校正脑容量后，女性在左半球以及左右顶叶显示出更高的复杂性，而男性在右颞叶以及左右枕叶显示出更高的复杂性。在左右额叶和右颞叶观察到非线性年龄效应。在两性中均观察到年龄效应的差异模式，男性受年龄影响的区域相对更多。在半球、额叶、顶叶和枕叶水平观察到显著更高的向右不对称性，在颞叶观察到更高的向左不对称性。在任何区域均未观察到年龄×性别×不对称性的交互作用。控制脑容量时，半球和颞叶的向左不对称性随年龄降低。男性半球间的不对称性显著低于女性，而在顶叶和枕叶的不对称性高于女性。这项工作提供了与年龄相关的性别和不对称性差异的独特模式，有助于未来开发正常大脑的性别特异性模型，以阐明这些模式在衰老过程中的认知功能意义。
