Brain Institute of Rio Grande do Sul (BraIns), PUCRS, Porto Alegre, Brazil.
School of Medicine, PUCRS, Porto Alegre, Brazil.
J Alzheimers Dis. 2021;81(4):1419-1428. doi: 10.3233/JAD-210063.
Individuals at 80 years of age or above with exceptional memory are considered SuperAgers (SA), an operationalized definition of successful cognitive aging. SA showed increased thickness and altered functional connectivity in the anterior cingulate cortex as a neurobiological signature. However, their metabolic alterations are yet to be uncovered.
Herein, a metabolic (FDG-PET), amyloid (PIB-PET), and functional (fMRI) analysis of SA were conducted.
Ten SA, ten age-matched older adults (C80), and ten cognitively normal middle-aged (C50) adults underwent cognitive testing and multimodal neuroimaging examinations. Anterior and posterior regions of the cingulate cortex and hippocampal areas were primarily examined, then subregions of anterior cingulate were segregated.
The SA group showed increased metabolic activity in the left and right subgenual anterior cingulate cortex (sACC, p < 0.005 corrected, bilateral) and bilateral hippocampi (right: p < 0.0005 and left: p < 0.005, both corrected) as compared to that in the C80 group. Amyloid deposition was above threshold in 30% of SA and C80 (p > 0.05). The SA group also presented decreased connectivity between right sACC and posterior cingulate (p < 0.005, corrected) as compared to that of the C80 group.
These results support the key role of sACC and hippocampus in SA, even in the presence of amyloid deposition. It also suggests that sACC may be used as a potential biomarker in older adults for exceptional memory ability. Further longitudinal studies measuring metabolic biomarkers may help elucidate the interaction between these areas in the cognitive aging process.
80 岁或以上记忆力超群的个体被认为是超级老年人（SA），这是成功认知老化的操作性定义。SA 的前扣带皮层表现出厚度增加和功能连接改变，这是其神经生物学特征。然而，他们的代谢变化尚未被揭示。
在此，对 SA 进行了代谢（FDG-PET）、淀粉样蛋白（PIB-PET）和功能（fMRI）分析。
10 名 SA、10 名年龄匹配的老年人（C80）和 10 名认知正常的中年人（C50）接受了认知测试和多模态神经影像学检查。主要检查了扣带前皮质的前后区域和海马区域，然后对扣带前皮质的亚区进行了分割。
与 C80 组相比，SA 组的左、右扣带前皮质的亚区（sACC，双侧 p<0.005 校正）和双侧海马（右侧：p<0.0005，左侧：p<0.005，均校正）代谢活性增加。30%的 SA 和 C80 有淀粉样蛋白沉积（p>0.05）。与 C80 组相比，SA 组右侧 sACC 与后扣带之间的连接减少（p<0.005，校正）。
这些结果支持 sACC 和海马在 SA 中的关键作用，即使存在淀粉样蛋白沉积也是如此。这也表明 sACC 可作为老年人认知能力超群的潜在生物标志物。进一步的纵向研究测量代谢生物标志物可能有助于阐明这些区域在认知老化过程中的相互作用。
