Schulze Evan T, Geary Elizabeth K, Susmaras Teresa M, Paliga James T, Maki Pauline M, Little Deborah M
Department of Neurology and Rehabilitation, University of Illinois at Chicago, Chicago, IL 60612, USA.
J Aging Res. 2011;2011:606871. doi: 10.4061/2011/606871. Epub 2011 Nov 16.
Aging studies consistently show a relationship between decreased gray matter volume and decreased performance on working memory tasks. Few aging studies have investigated white matter changes in relation to functional brain changes during working memory tasks. Twenty-five younger and 25 older adults underwent anatomical magnetic resonance imaging (MRI) scans to measure gray matter volume, diffusion tensor imaging (DTI) to measure fractional anisotropy (FA) as a measure of white matter integrity, and functional magnetic resonance imaging (fMRI) while performing a working memory task. Significant increases in activation (fMRI) were seen in the left dorsal and ventral lateral prefrontal cortex with increased working memory load and with increased age (older showing greater bilateral activation). Partial correlational analyses revealed that even after controlling for age, frontal FA correlated significantly with fMRI activation during performance on the working memory task. These findings highlight the importance of white matter integrity in working memory performance associated with normal aging.
衰老研究一直表明，灰质体积减少与工作记忆任务表现下降之间存在关联。很少有衰老研究调查过在工作记忆任务期间，白质变化与大脑功能变化之间的关系。25名年轻人和25名老年人接受了解剖磁共振成像（MRI）扫描以测量灰质体积，接受了扩散张量成像（DTI）以测量分数各向异性（FA）作为白质完整性的指标，并在执行工作记忆任务时进行了功能磁共振成像（fMRI）。随着工作记忆负荷增加和年龄增长（老年人显示出更大的双侧激活），左背侧和腹侧外侧前额叶皮层的激活（fMRI）显著增加。偏相关分析显示，即使在控制年龄后，额叶FA与工作记忆任务执行期间的fMRI激活也显著相关。这些发现突出了白质完整性在与正常衰老相关的工作记忆表现中的重要性。
