SickKids Research Institute, Toronto, Ontario, Canada.
University of Toronto, Department of Paediatrics, Toronto, Ontario, Canada.
Brain Behav. 2023 Sep;13(9):e3158. doi: 10.1002/brb3.3158. Epub 2023 Jul 21.
The N400 is an electrophysiological component that reflects lexical access and integration of words with mental representations.
Thirty-five young children with a range of language capabilities (n = 21 neurotypical controls, 10 males, mean age = 6.3 ± 0.9 years; n = 14 children with autism, 12 males, mean age = 6.4 ± 1.1 years) completed an auditory semantic categorization paradigm to evoke the N400. Electroencephalograph (EEG) data were acquired with a 64-channel electrode cap as children listened via ear inserts to binaurally presented single syllable words and decided whether the words were congruent (in) or incongruent (out) with a pre-specified category. EEG data were filtered, epoched, and averaged referenced, and global field power (GFP) was computed. The amplitude of the N400 peak in the GFP was submitted to a multiple linear regression analysis.
N400 amplitude was found to predict language scores only for the children with ASD who have language scores in the normal range (r = 0.72).
This finding that N400 amplitude only predicted language scores in children with ASD and normal language scores suggests that these children may rely more on basic semantic processing (as reflected by the N400) and less on anticipating and predicting upcoming words. This suggests preferential utilization of a bottom-up strategy to access higher order language.
N400 是一种反映词汇获取和心理表征中单词整合的电生理成分。
35 名语言能力各异的幼儿（n = 21 名神经典型对照组，男性 10 名，平均年龄 6.3 ± 0.9 岁；n = 14 名自闭症儿童，男性 12 名，平均年龄 6.4 ± 1.1 岁）完成了听觉语义分类范式，以引发 N400。脑电图（EEG）数据是通过一个 64 通道电极帽采集的，当孩子们通过耳塞双耳聆听单音节单词并决定这些单词是否与特定类别一致（in）或不一致（out）时，就会记录 EEG 数据。EEG 数据经过滤波、分期和均方根参考，并计算全局场功率（GFP）。GFP 中 N400 峰的振幅被提交给多元线性回归分析。
只有在语言能力正常的自闭症儿童中，N400 振幅与语言得分相关（r = 0.72）。
这一发现表明，N400 振幅仅能预测语言得分正常的自闭症儿童的语言得分，这表明这些儿童可能更多地依赖于基本的语义处理（如 N400 所反映的），而较少依赖于预测和预测即将到来的单词。这表明他们更倾向于使用自下而上的策略来获取更高层次的语言。
