Imaging Sciences, Imaging Institute, Cleveland Clinic, 9500 Euclid Ave / U15, Cleveland, OH, 44195, USA.
Genomic Medicine Institute, Cleveland Clinic, Cleveland, OH, USA.
Brain Imaging Behav. 2021 Aug;15(4):2051-2060. doi: 10.1007/s11682-020-00399-z. Epub 2020 Oct 18.
Studies of resting-state functional connectivity MRI in Alzheimer's disease suggest that disease stage plays a role in functional changes of the default mode network. Individuals with the genetic disorder Down syndrome show an increased incidence of early-onset Alzheimer's-type dementia, along with early and nearly universal neuropathologic changes of Alzheimer's disease. The present study examined high-resolution functional connectivity of the default mode network in 11 young adults with Down syndrome that showed no measurable symptoms of dementia and 11 age- and sex-matched neurotypical controls. We focused on within-network connectivity of the default mode network, measured from both anterior and posterior aspects of the cingulate cortex. Sixty-eight percent of connections to the posterior cingulate and 26% to the anterior cingulate showed reduced strength in the group with Down syndrome (p < 0.01). The Down syndrome group showed increased connectivity strength from the anterior cingulate to the bilateral inferior frontal gyri and right putamen (p < 0.005). In an exploratory analysis, connectivity in the group with Down syndrome showed regional relationships to plasma measures of inflammatory markers and t-tau. In non-demented adults with Down syndrome, functional connectivity within the default mode network may be analogous to changes reported in preclinical Alzheimer's disease, and warrants further investigation as a measure of dementia risk.
对阿尔茨海默病静息态功能连接磁共振成像的研究表明，疾病阶段在默认模式网络的功能变化中起作用。患有唐氏综合征等遗传疾病的个体，阿尔茨海默病样痴呆的发病较早，且存在早期和几乎普遍的阿尔茨海默病神经病理学变化。本研究检查了 11 名唐氏综合征青年，他们没有表现出可测量的痴呆症状，且与 11 名年龄和性别匹配的神经典型对照者的默认模式网络的高分辨率功能连接。我们重点关注了扣带回皮质前后两个部位的默认模式网络的网络内连接。在后扣带回有 68%的连接，在前扣带回有 26%的连接，其强度在唐氏综合征组中降低（p < 0.01）。唐氏综合征组中，从前扣带回到双侧额下回和右侧壳核的连接强度增加（p < 0.005）。在探索性分析中，唐氏综合征组的连接与血浆炎症标志物和 t-tau 的测量值呈区域关系。在无痴呆的唐氏综合征成年人中，默认模式网络内的功能连接可能类似于在临床前阿尔茨海默病中报告的变化，因此需要进一步研究，作为痴呆风险的衡量标准。
