Child Health Research Centre, Faculty of Medicine, The University of Queensland, South Brisbane, 4101, QLD, Brisbane, Australia; QIMR Berghofer Medical Research Institute, Brisbane, QLD, 4006, Australia.
School of Health & Rehabilitation Sciences, The University of Queensland, St Lucia, 4067, QLD, Brisbane, Australia; MultiLit Research Unit, MultiLit Pty Ltd, Macquarie Park, 2113, NSW, Sydney, Australia.
Neuropsychologia. 2023 May 3;183:108532. doi: 10.1016/j.neuropsychologia.2023.108532. Epub 2023 Mar 9.
The early school years shape a young brain's capability to comprehend and contextualize words within milliseconds of exposure. Parsing word sounds (phonological interpretation) and word recognition (enabling semantic interpretation) are integral to this process. Yet little is known about the causal mechanisms of cortical activity during these early developmental stages. In this study, we aimed to explore these causal mechanisms via dynamic causal modelling of event-related potentials (ERPs) acquired from 30 typically developing children (ages 6-8 years) as they completed a spoken word-picture matching task. Source reconstruction of high-density electroencephalography (128 channels) was used to ascertain differences in whole-brain cortical activity during semantically "congruent" and "incongruent" conditions. Source activations analyzed during the N400 ERP window identified significant regions-of-interest (p<.05) localized primarily in the right hemisphere when contrasting congruent and incongruent word-picture stimuli. Dynamic causal models (DCMs) were tested on source activations in the fusiform gyrus (rFusi), inferior parietal lobule (rIPL), inferior temporal gyrus (rITG) and superior frontal gyrus (rSFG). DCM results indicated that a fully connected bidirectional model with self-(inhibiting) connections over rFusi, rIPL and rSFG provided the highest model evidence, based on exceedance probabilities derived from Bayesian statistical inferences. Connectivity parameters of rITG and rSFG regions from the winning DCM were negatively correlated with behavioural measures of receptive vocabulary and phonological memory (p<.05), such that lower scores on these assessments corresponded with increased connectivity between temporal pole and anterior frontal regions. The findings suggest that children with lower language processing skills required increased recruitment of right hemisphere frontal/temporal areas during task performance.
早期的学校教育塑造了年轻大脑在接触单词后的毫秒内理解和上下文理解单词的能力。解析单词的发音（语音解释）和识别单词（实现语义解释）是这个过程的组成部分。然而，对于这些早期发育阶段大脑皮质活动的因果机制知之甚少。在这项研究中，我们旨在通过对 30 名正常发育的儿童（6-8 岁）在完成口语单词-图片匹配任务时获得的事件相关电位（ERP）进行动态因果建模来探索这些因果机制。高密度脑电图（128 通道）的源重建用于确定语义“一致”和“不一致”条件下整个大脑皮质活动的差异。在 N400 ERP 窗口期间分析的源激活确定了在对比一致和不一致的单词-图片刺激时主要位于右半球的显著感兴趣区域（p<.05）。在梭状回（rFusi）、下顶叶（rIPL）、下颞叶（rITG）和额上回（rSFG）的源激活上测试了动态因果模型（DCM）。结果表明，基于贝叶斯统计推断得出的超出概率，具有自我（抑制）连接的完全连接双向模型在 rFusi、rIPL 和 rSFG 上提供了最高的模型证据。来自获胜 DCM 的 rITG 和 rSFG 区域的连接参数与接受性词汇和语音记忆的行为测量呈负相关（p<.05），即这些评估得分较低对应于颞极和额前区域之间的连接增加。研究结果表明，语言处理能力较低的儿童在任务表现中需要更多地招募右侧额颞区。
