Brain, Behavior & Aging Research Center, VA Greater Los Angeles Healthcare System Building 158, Room 167, 11301 Wilshire Boulevard, Los Angeles, CA 90073, USA; Dept. of Psychiatry & Biobehavioral Sciences, David Geffen School of Medicine at UCLA, 300 Medical Plaza, Los Angeles, CA 90095, USA.
Brain, Behavior & Aging Research Center, VA Greater Los Angeles Healthcare System Building 158, Room 167, 11301 Wilshire Boulevard, Los Angeles, CA 90073, USA; Dept. of Psychiatry & Biobehavioral Sciences, David Geffen School of Medicine at UCLA, 300 Medical Plaza, Los Angeles, CA 90095, USA.
Neuroimage Clin. 2018 Jun 12;19:970-981. doi: 10.1016/j.nicl.2018.06.014. eCollection 2018.
Poor executive functioning increases risk of decline in Mild Cognitive Impairment (MCI). Executive functioning can be conceptualized within the framework of working memory. While some components are responsible for maintaining representations in working memory, the central executive is involved in the manipulation of information and creation of new representations. We aimed to examine the neural correlates of these components of working memory using a maintenance working memory and visuospatial reasoning task. Twenty-five patients with amnestic MCI and 19 elderly controls (EC) completed functional MRI during reasoning and maintenance working memory tasks. In MCI, maintenance working memory was associated with hypoactivation of right frontoparietal regions and hyperactivation of left prefrontal cortex, coupled with attenuation of default mode network (DMN) relative to EC. During reasoning, MCI showed hypoactivation of parietal regions, coupled with attenuation of anterior DMN and increased deactivation of posterior DMN relative to EC. Comparing the reasoning task to the maintenance working memory task yields the central executive. In MCI, the central executive showed hypoactivation of right parietal lobe and increased deactivation of posterior DMN compared to EC. Consistent with prior work on executive functioning, MCI show different neural circuitry during visuospatial reasoning, including changes to both task positive frontoparietal regions, as well as to deactivation patterns within the DMN. Both hyperactivation of task positive networks and increased deactivation of DMN may be compensatory.
执行功能障碍会增加轻度认知障碍（MCI）恶化的风险。执行功能可以在工作记忆的框架内进行概念化。虽然某些组件负责在工作记忆中保持表示，但中央执行器则涉及信息的操作和新表示的创建。我们旨在使用维持工作记忆和视空间推理任务来检查工作记忆这些成分的神经相关性。25 名有记忆障碍的 MCI 患者和 19 名老年对照组（EC）在推理和维持工作记忆任务期间完成了 fMRI。在 MCI 中，维持工作记忆与右额顶叶区域的低激活和左前额叶皮层的高激活有关，与 EC 相比，默认模式网络（DMN）的衰减有关。在推理过程中，MCI 显示顶叶区域的低激活，与前 DMN 的衰减以及与 EC 相比后 DMN 的去激活增加有关。将推理任务与维持工作记忆任务进行比较，可以得出中央执行器。在 MCI 中，与 EC 相比，右顶叶和后 DMN 的中央执行器显示出低激活。与执行功能的先前研究一致，MCI 在视空间推理过程中显示出不同的神经回路，包括任务积极的额顶叶区域的变化，以及 DMN 内去激活模式的变化。任务积极网络的高激活和 DMN 的去激活增加可能是补偿性的。
