Since the early 2000s, neurocognitive research on second language (L2) acquisition has been controversial as to how plastic the human brain is after puberty. Recent studies have extended this debate to first language loss (L1 attrition). This article gives an overview of the first event‐related brain potential (ERP) studies on L1 attrition and L2 learning and discusses their implications for our understanding of the bilingual brain. We will address the highly controversial question of whether L1 morphosyntax is subject to attrition in adult migrants. One previous ERP study on grammatical gender in German migrants failed to find such effects. However, ERP work on grammatical structures in English‐dominant Italian attriters demonstrated that they perceived a grammatical sentence in their L1 as ungrammatical if it violated the L2 grammar. These data suggest that the adult brain remains plastic for both L2 and L1.

中文翻译：

---

成年期的大脑可塑性—主要使用L2后，词汇和词法中L1耗损的ERP证据

自2000年代初以来，关于第二语言（L2）习得的神经认知研究一直争议着青春期后人脑的可塑性。最近的研究将这种争论扩大到了母语丧失（L1减员）。本文概述了有关L1耗损和L2学习的第一项事件相关的大脑潜能（ERP）研究，并讨论了它们对我们对双语大脑的理解的意义。我们将解决一个备受争议的问题，即成年移民是否会遭受L1吗啡句法的消耗。先前的一项ERP研究对德国移民的语法性别没有发现这种影响。但是，ERP在英语占主导地位的意大利磨工的语法结构方面的工作表明，如果他们违反了L2语法，他们会认为L1中的语法句子不合语法。