Centre for Neurolinguistics and Psycholinguistics (CNPL), Vita-Salute San Raffaele University, Italy; Faculty of Psychology, Vita-Salute San Raffaele University and Scientific Institute San Raffaele, Milan, Italy.
Centre for Neurolinguistics and Psycholinguistics (CNPL), Vita-Salute San Raffaele University, Italy.
Neuroimage. 2020 Jan 15;205:116306. doi: 10.1016/j.neuroimage.2019.116306. Epub 2019 Oct 22.
There is currently no agreement on which factor modulates most effectively and enduringly brain plasticity in bilingual individuals. Grouping heterogeneous linguistic profiles under a dichotomous condition (bilingualism versus monolingualism) may obscure critical aspects of language experience underlying neural changes, thus leading to variable and often conflicting findings. In the present study, we overcome these limitations by analyzing the individual and joint contribution of L2 AoA, proficiency and usage - all measured as continuous variables - on the resting-state functional connectivity of the brain networks mediating the specific demands of bilingual language processing: the language network and the executive control network. Our results indicate that bilingual experience - defined as a continuous and multifaceted phenomenon - impacts brain plasticity by modulating the functional connectivity both within and between language and control networks. Each experience-related factor considered played a role in changing the connectivity of these regions. Moreover, the effect of AoA was modulated by proficiency and usage. These findings shed new light on the importance of modeling bilingualism as a gradient measure rather than an all-or-none phenomenon.
目前，对于哪种因素能最有效地调节双语者的大脑可塑性，尚无定论，且这种可塑性具有持久性。将不同的语言模式归入二分类条件（双语者与单语者）下，可能会掩盖语言经验对神经变化的重要影响，从而导致结果具有变异性，且常常相互矛盾。在本研究中，我们通过分析 L2 年龄、熟练程度和使用情况（均作为连续变量测量）对大脑网络静息态功能连接的个体和联合贡献，克服了这些局限性，这些大脑网络介导着双语语言处理的特定需求：语言网络和执行控制网络。我们的研究结果表明，双语经验——定义为一种连续的、多方面的现象——通过调节语言和控制网络内部和之间的功能连接来影响大脑可塑性。所考虑的每个与经验相关的因素都在改变这些区域的连接中发挥了作用。此外，年龄的影响受到熟练程度和使用情况的调节。这些发现为将双语作为一种渐变的衡量标准而不是全有或全无的现象来建模的重要性提供了新的启示。
