Dual/multiple language use has been shown to affect cognition and its neural substrate, although the replicability of such findings varies, partially due to neglecting the role of interindividual variability in bilingual experience. To address this, we operationalized the main bilingual experience factors as continuous variables, investigating their effects on executive control performance and neural substrate deploying a Flanker task and structural magnetic resonance imaging. First, higher L2 proficiency predicted better executive performance. Second, neuroimaging results indicated that bilingualism-related neuroplasticity may peak at a certain stage of bilingual experience and eventually revert, possibly following functional specialization. Importantly, experienced bilinguals optimized behavioral performance independently of volumetric variations, suggesting a degree of performance gain even with lower GMV. Hence, the effects of bilingualism on cognition may evolve with experience, with improvements in functional efficiency eventually replacing structural changes. We conclude that individual differences in bilingual experience modulate cognitive and neural consequences of bilingualism.

中文翻译：

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双语经验的个体差异调节执行控制网络和表现：行为和结构神经影像学证据

双语/多语使用已被证明会影响认知及其神经基础，尽管这些发现的可复制性各不相同，部分原因是忽略了双语体验中个体间变异性的作用。为了解决这个问题，我们将主要的双语体验因素作为连续变量进行操作，研究它们对执行控制性能和部署 Flanker 任务和结构磁共振成像的神经基质的影响。首先，较高的 L2 熟练度预示着更好的执行绩效。其次，神经影像学结果表明，双语相关的神经可塑性可能在双语体验的某个阶段达到顶峰并最终恢复，可能在功能特化之后。重要的，经验丰富的双语者独立于体积变化优化了行为表现，这表明即使在 GMV 较低​​的情况下也能获得一定程度的性能提升。因此，双语对认知的影响可能会随着经验而发展，功能效率的提高最终会取代结构变化。我们得出结论，双语经验的个体差异调节双语的认知和神经后果。