Shaked Danielle, Katzel Leslie I, Seliger Stephen L, Gullapalli Rao P, Davatzikos Christos, Erus Guray, Evans Michele K, Zonderman Alan B, Waldstein Shari R
Department of Psychology.
Division of Gerontology and Geriatric Medicine.
Neuropsychology. 2018 Nov;32(8):985-995. doi: 10.1037/neu0000484. Epub 2018 Sep 13.
Lower socioeconomic status (SES) is related to poorer cognitive performance, but the neural underpinnings of this relation are not fully understood. This study examined whether SES-linked decrements in executive function were mediated by smaller dorsolateral prefrontal cortex (DLPFC) volumes. Given the literature demonstrating that SES-brain relations differ by race, we examined whether race moderated these mediations.
Participants were 190 socioeconomically diverse, self-identified African American (AA) and White adults from the Healthy Aging in Neighborhoods of Diversity across the Life Span (HANDLS) SCAN study. Regional brain volumes were derived using T1-weighted MP-RAGE images. Adjusting for age and sex, moderated mediation analyses examined if the DLPFC mediated SES-executive function relations differently across racial groups. Executive function was measured using Trail Making Test part B (Trails B), Digit Span Backwards (DSB), and verbal fluency.
Moderated mediation demonstrated that DLPFC volume significantly mediated the association between SES and Trails B in Whites (lower confidence interval [CI] = 0.01; upper CI = 0.07), but not in AAs (lower CI = -0.05; upper CI = 0.01). No mediations were found for DSB or verbal fluency, although SES was related to all tests.
The DLPFC may be important in the association of SES and mental flexibility for White, but not AA adults. It is possible that the well-replicated advantages of high SES among Whites do not readily translate, on average, to AAs. These findings highlight the importance of brain volume for cognitive functioning, while adding to the literature on sociodemographic health disparities. (PsycINFO Database Record (c) 2018 APA, all rights reserved).
社会经济地位较低（SES）与较差的认知表现相关，但这种关系的神经基础尚未完全明确。本研究考察了执行功能方面与SES相关的减退是否由较小的背外侧前额叶皮质（DLPFC）体积介导。鉴于有文献表明SES与大脑的关系因种族而异，我们考察了种族是否调节了这些中介作用。
参与者来自“跨生命周期的邻里多样性健康老龄化”（HANDLS）扫描研究，共190名社会经济背景各异、自我认定为非裔美国人（AA）和白人的成年人。使用T1加权MP-RAGE图像得出区域脑容量。在调整年龄和性别后，通过调节中介分析考察DLPFC在不同种族群体中对SES与执行功能关系的中介作用是否不同。执行功能通过连线测验B部分（Trails B）、倒背数字（DSB）和言语流畅性进行测量。
调节中介分析表明，DLPFC体积在白人中显著介导了SES与Trails B之间的关联（置信区间下限[CI]=0.01；上限CI=0.07），但在非裔美国人中并非如此（下限CI=-0.05；上限CI=0.01）。对于DSB或言语流畅性未发现中介作用，尽管SES与所有测试均相关。
DLPFC可能在白人而非非裔美国成年人的SES与心理灵活性的关联中起重要作用。高SES在白人中得到充分验证的优势平均而言可能无法直接转化为非裔美国人的优势。这些发现凸显了脑容量对认知功能的重要性，同时也丰富了关于社会人口统计学健康差异的文献。（《心理学文摘数据库记录》（c）2018美国心理学会，保留所有权利）
