应用基于体素的形态测量学分析工作记忆老化的脑灰质萎缩基础

Working memory decline and gray matter atrophy in healthy aged people: A voxel-based morphometry study

目的利用基于体素的形态测量学(VBM)方法探讨老年人工作记忆能力衰退与脑灰质萎缩间的关系。方法在30名老年人(老年组)和38名青壮年人(对照组)中分别进行keep-track任务和2-back任务两种工作记忆任务检测。对所有受试者进行高分辨力MR扫描,并使用统计参数图(SPM)8软件进行VBM分析,比较老年组与对照组的脑灰质体积差异,并在老年组内利用多元回归分析寻找与工作记忆任务能力下降相关的责任萎缩脑区。结果与对照组相比,老年组工作记忆能力显著衰退,且出现广泛的脑灰质萎缩。老年组中,与keep-track任务能力相关的萎缩脑区主要位于双侧前额叶中下部、运动前区、顶叶后下部和小脑;与2-back任务相关的萎缩脑区主要位于左侧的前额叶下部、运动前区和颞叶。左腹侧运动前区(BA6)皮层的灰质体积与两个任务的行为学数据均存在显著相关性。结论老年人工作记忆能力下降与工作记忆神经网络的灰质萎缩有关。

Objective To explore the relationship between the decline of working memory and gray matter atrophy in nor- mal aging with voxel-based morphometry （VBM） method. Methods Keep-track task and 2-back task were used to observe working memory in 30 old people （aged group） and 38 young people （control group）. High resolution MR scan was per- formed in all participants, and MRI data were analyzed using VBM with statistical parametric mapping （SPM） 8. Gray matter volume of the two groups were compared, while in the aged group multiple regression was done between gray matter volume and the behavioral scores of the two working memory tasks to find atrophic brain areas responsible for the decline of working memory. Results Compared with control group, the aged group showed significant decline of working memory and wide gray matter atrophy. In the aged group, atrophy of gray matter associated with low score in keep-track task was found in bilateral middle and inferior prefrontal cortex, premotor cortex, posterior parietal lobes and cerebellum. Atrophy of gray matter associated with high error rate in 2 back task was found in left inferior prefrontal cortex, premotor cortex and temporal lobe. The volume of gray matter of left ventral premotor cortex （BA6） was related to both behavioral scores in the two working memory tasks. Conclusion The decline of working memory in healthy aging is related to gray matter atrophy of the working memory neural network.