Rossi Eleonora, Cheng Hu, Kroll Judith F, Diaz Michele T, Newman Sharlene D
Department of Psychology and Sociology, California State Polytechnic University, Pomona, Pomona, CA, United States.
Department of Psychology, University of California, Riverside, Riverside, CA, United States.
Front Psychol. 2017 Nov 21;8:2040. doi: 10.3389/fpsyg.2017.02040. eCollection 2017.
Morphological brain changes as a consequence of new learning have been widely established. Learning a second language (L2) is one such experience that can lead to rapid structural neural changes. However, still relatively little is known about how levels of proficiency in the L2 and the age at which the L2 is learned influence brain neuroplasticity. The goal of this study is to provide novel evidence for the effect of bilingualism on white matter structure in relatively proficient but late L2 learners who acquired the second language after early childhood. Overall, the results demonstrate a significant effect on white matter fractional anisotropy (FA) as a function of L2 learning. Higher FA values were found in a broad white matter network including the anterior thalamic radiation (ATR), the inferior fronto-occipital fasciculus (IFOF), the Uncinate Fasciculus (UF), and the inferior longitudinal fasciculus (ILF). Moreover, FA values were correlated with age of L2 acquisition, suggesting that learning an L2, even past childhood, induces neural changes. Finally, these results provide some initial evidence that variability in the age of L2 acquisition has important consequences for neural plasticity.
作为新学习的结果，大脑的形态学变化已得到广泛证实。学习第二语言（L2）就是这样一种能够导致快速结构性神经变化的经历。然而，对于L2的熟练程度以及学习L2的年龄如何影响大脑神经可塑性，人们仍然知之甚少。本研究的目的是为双语对相对熟练但较晚学习L2（在童年早期之后习得第二语言）的学习者白质结构的影响提供新的证据。总体而言，结果表明L2学习对白质分数各向异性（FA）有显著影响。在包括丘脑前辐射（ATR）、额枕下束（IFOF）、钩束（UF）和下纵束（ILF）在内的广泛白质网络中发现了更高的FA值。此外，FA值与L2习得年龄相关，这表明学习L2，即使是在童年之后，也会诱发神经变化。最后，这些结果提供了一些初步证据，表明L2习得年龄的差异对神经可塑性有重要影响。
