Research suggests social connectedness may help older adults with dementia maintain cognitive functionality and quality of life. However, little is known about its specific social and biological mechanisms. This paper proposes two pathways through social bridging (i.e., cognitive enrichment through expansive social networks) and bonding (i.e., neuroendocrine benefits of integration in cohesive social networks). We provide preliminary evidence for these pathways using neuroimaging, cognitive, and egocentric social network data from the Social Networks and Alzheimer's Disease (SNAD) study (N = 280). We found that network size, density, and presence of weak ties (i.e., social bridging) moderated the association between brain atrophy and cognitive function, while marriage/cohabitation (i.e., social bonding) moderated the association between perceived stress and cognitive function. We argue that social connectedness may have downstream implications for multiple pathophysiological processes in cognitive aging, even negating existing structural damage to the brain, making it a strong candidate for clinical or policy intervention.

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为什么认知“青春之泉”可能在上游：通过社会联系降低痴呆症风险和恢复力的途径

研究表明，社会联系可能有助于患有痴呆症的老年人保持认知功能和生活质量。然而，对其具体的社会和生物学机制知之甚少。本文提出了通过社交桥接（即通过广泛的社交网络丰富认知）和结合（即融入有凝聚力的社交网络的神经内分泌益处）的两条途径。我们使用来自社交网络和阿尔茨海默病 (SNAD) 研究 (N = 280) 的神经影像学、认知和以自我为中心的社交网络数据为这些途径提供了初步证据。我们发现网络规模、密度和弱关系（即社会桥接）的存在缓和了脑萎缩和认知功能之间的关联，而婚姻/同居（即，社会联系）调节感知压力与认知功能之间的关联。我们认为，社会联系可能对认知老化的多种病理生理过程产生下游影响，甚至可以抵消现有的大脑结构损伤，使其成为临床或政策干预的有力候选者。