Table_3_Fitness Level Influences White Matter Microstructure in Postmenopausal Women.docx

Aerobic exercise has both neuroprotective and neurorehabilitative benefits. However, the underlying mechanisms are not fully understood and need to be investigated, especially in postmenopausal women, who are at increased risk of age-related disorders such as Alzheimer’s disease and stroke. To advance our understanding of the potential neurological benefits of aerobic exercise in aging women, we examined anatomical and functional responses that may differentiate women of varying cardiorespiratory fitness using neuroimaging and neurophysiology. A total of 35 healthy postmenopausal women were recruited (59 ± 3 years) and cardiorespiratory fitness estimated (22–70 mL/kg/min). Transcranial magnetic stimulation was used to assess -aminobutyric acid (GABA) and glutamate (Glu) receptor function in the primary motor cortex (M1), and magnetic resonance spectroscopy (MRS) was used to quantify GABA and Glu concentrations in M1. Magnetic resonance imaging was used to assess mean cortical thickness (MCT) of sensorimotor and frontal regions, while the microstructure of sensorimotor and other white matter tracts was evaluated through diffusion tensor imaging. Regression analysis revealed that higher fitness levels were associated with improved microstructure in pre-motor and sensory tracts, and the hippocampal cingulum. Fitness level was not associated with MCT, MRS, or neurophysiology measures. These data indicate that, in postmenopausal women, higher cardiorespiratory fitness is linked with preserved selective white matter microstructure, particularly in areas that influence sensorimotor control and memory.

有氧运动兼具神经保护与神经康复益处，但其潜在机制尚未完全阐明，有待进一步研究，尤其针对绝经后女性群体——该群体罹患阿尔茨海默病（Alzheimer’s disease）、卒中（stroke）等年龄相关性疾病的风险显著升高。为加深对有氧运动在老年女性中潜在神经获益的理解，本研究借助神经影像学与神经生理学手段，分析了可区分不同心肺适能水平女性的解剖学与功能响应特征。本研究共招募35名健康绝经后女性（年龄59±3岁），并评估了其心肺适能（范围22–70 mL/kg/min）。采用经颅磁刺激（Transcranial magnetic stimulation）评估初级运动皮层（primary motor cortex, M1）内γ-氨基丁酸（γ-aminobutyric acid, GABA）与谷氨酸（glutamate, Glu）受体功能，同时借助磁共振波谱（magnetic resonance spectroscopy, MRS）定量M1区域内GABA与Glu的浓度。通过磁共振成像评估感觉运动区与额叶皮层的平均皮层厚度（mean cortical thickness, MCT）；同时借助弥散张量成像（diffusion tensor imaging）分析感觉运动束及其他白质束的微观结构特征。回归分析结果显示，更高的心肺适能水平与运动前束、感觉束及海马扣带回的微观结构改善呈显著相关；但心肺适能水平与MCT、MRS及神经生理学指标无显著关联。本研究数据表明，在绝经后女性群体中，更高的心肺适能水平与特定白质微观结构的完整性保持相关，尤其在影响感觉运动控制与记忆的脑区中。