Cantiani Chiara, Riva Valentina, Piazza Caterina, Melesi Giulia, Mornati Giulia, Bettoni Roberta, Marino Cecilia, Molteni Massimo
Child Psychopathology Unit, Scientific Institute, IRCCS Eugenio Medea, Bosisio Parini, Lecco, Italy.
Child Psychopathology Unit, Scientific Institute, IRCCS Eugenio Medea, Bosisio Parini, Lecco, Italy.
Neuropsychologia. 2017 Aug;103:115-130. doi: 10.1016/j.neuropsychologia.2017.06.031. Epub 2017 Jun 30.
Children begin to establish lexical-semantic representations during their first year of life, resulting in a rapid growth of vocabulary around 18-24 months of age. The neural mechanisms underlying this initial ability to map words onto conceptual representations remain relatively unknown. In the present study, the electrophysiological underpinnings of these mechanisms are explored during the critical phase of lexical acquisition using a picture-word matching paradigm. Event-Related Potentials (ERPs) elicited by words (either congruous or incongruous with the previous picture context) and pseudo-words are investigated in 20-month-old toddlers (N = 20) and compared to those elicited in a sample of adults (N = 20), reflecting the final and efficient system, and a sample of toddlers at familial risk for language and learning impairment (LLI, N = 15). The results suggest that the architecture underlying spoken word representation and processing is constant throughout development, even if some differences between children and adults emerged. Interestingly, children seem to be faster than adults in processing incongruent words, probably because relying on a different and more superficial strategy. This early strategy does not seem to be present in children at risk for LLI. In addition, both groups of children do not show different and specific electrophysiological underpinnings in response to real but incongruent words and unknown words, suggesting that during the critical phase of lexical acquisition any potential word is processed in a similar way. Overall, children at risk for LLI turned out to be sensitive to verbal incongruity of the lexical-semantic context, although some differences from typically developing children emerged, reflecting slower processing and less automatic responses. Taken together, the findings of this study pave the way to further research to investigate these effects in clinical and at-risk populations with the general purpose of disentangling the underlying mechanisms of lexical acquisition, and potentially predicting later language (dis)abilities.
儿童在生命的第一年开始建立词汇语义表征，这导致在18至24个月大时词汇量迅速增长。将单词映射到概念表征的这种初始能力背后的神经机制仍然相对未知。在本研究中，使用图片-单词匹配范式，在词汇习得的关键阶段探索这些机制的电生理基础。研究了20个月大的幼儿（N = 20）对单词（与先前图片语境一致或不一致）和伪词诱发的事件相关电位（ERP），并将其与成年人样本（N = 20）诱发的ERP进行比较，成年人样本反映了最终且高效的系统，同时还与有语言和学习障碍（LLI）家族风险的幼儿样本（N = 15）进行了比较。结果表明，即使儿童和成年人之间出现了一些差异，口语单词表征和处理的基础结构在整个发育过程中是恒定的。有趣的是，儿童在处理不一致的单词时似乎比成年人更快，这可能是因为他们依赖于一种不同且更表面的策略。这种早期策略似乎在有LLI风险的儿童中不存在。此外，两组儿童在对真实但不一致的单词和未知单词的反应中，没有表现出不同的特定电生理基础，这表明在词汇习得的关键阶段，任何潜在的单词都以类似的方式进行处理。总体而言，有LLI风险的儿童对词汇语义语境的言语不一致很敏感，尽管与典型发育儿童存在一些差异，反映出处理速度较慢和反应不太自动。综上所述，本研究结果为进一步研究铺平了道路，以便在临床和高危人群中研究这些影响，其总体目的是理清词汇习得的潜在机制，并有可能预测后期的语言（失）能。
