Activity in the fronto-parietal multiple-demand network is robustly associated with individual differences in working memory and fluid intelligence.

Numerous brain lesion and fMRI studies have linked individual differences in executive abilities and fluid intelligence to brain regions of the fronto-parietal “multiple-demand” (MD) network. Yet, fMRI studies have yielded conflicting evidence as to whether better executive abilities are associated with stronger or weaker MD activations and whether this relationship is restricted to the MD network. Here, in a large-sample (n=216) fMRI investigation, we found that stronger activity in MD regions – functionally defined in individual participants – was robustly associated with more accurate and faster responses on a spatial working memory task performed in the scanner, as well as fluid intelligence measured independently (n=114). In line with some prior claims about a relationship between language and fluid intelligence, we also found a weak association between activity in the brain regions of the left fronto-temporal language network during an independent passive reading task, and performance on the working memory task. However, controlling for the level of MD activity abolished this relationship, whereas the MD activity-behavior association remained highly reliable after controlling for the level of activity in the language network. Finally, we demonstrate how unreliable MD activity measures, coupled with small sample sizes, could falsely lead to the opposite, negative, association that has been reported in some prior studies. Taken together, these results demonstrate that a core component of individual differences variance in executive abilities and fluid intelligence is selectively and robustly positively associated with the level of activity in the MD network, a result that aligns well with lesion studies.

许多大脑病变和功能磁共振成像的研究将执行能力和流体智能的个体差异与额叶 - 大型“多个需求”（MD）网络的大脑区域联系起来。在大型样本（n = 216）fMRI调查中，这种关系更强或较弱发现在单个参与者功能上定义的MD区域中的强大活动与在扫描仪中执行的空间工作记忆任务以及独立测量的流体智能（n = 114）都与更准确，更快的响应相关联（n = 114）关于语言与流体智能之间关系的一些先验主张，我们还发现在左额额局部语言网络的大脑区域之间的活动较弱但是，独立的被动阅读任务和工作记忆任务的性能。我们证明了不可靠的MD活性度量如何与小样本大小相结合，可能会导致相反的，负相关的关联，这在某些先前的研究中已被报道。这些结果表明，执行能力和流体智能中个体差异差异的核心组成部分与MD网络中的活动水平有选择性，牢固地相关，这一结果与病变研究很好地保持一致。