The Frederick J. and Marion A. Schindler Cognitive Neurophysiology Laboratory, The Del Monte Institute for Neuroscience, Department of Neuroscience, University of Rochester School of Medicine and Dentistry, Rochester, NY 14620, USA.
The Frederick J. and Marion A. Schindler Cognitive Neurophysiology Laboratory, The Del Monte Institute for Neuroscience, Department of Neuroscience, University of Rochester School of Medicine and Dentistry, Rochester, NY 14620, USA.
Neuroscience. 2024 Nov 12;560:238-253. doi: 10.1016/j.neuroscience.2024.10.008. Epub 2024 Oct 5.
Language comprehension requires semantic processing of individual words and their context within a sentence. Well-characterized event-related potential (ERP) components (the N400 and late positivity component (LPC/P600)) provide neuromarkers of semantic processing, and are robustly evoked when semantic errors are introduced into sentences. These measures are useful for evaluating semantic processing in clinical populations, but it is not known whether they can be evoked in more severe neurodevelopmental disorders where explicit attention to the sentence inputs cannot be objectively assessed (i.e., when sentences are passively listened to). We evaluated whether N400 and LPC/P600 could be detected in adolescents who were explicitly ignoring sentence inputs. Specifically, it was asked whether explicit attention to spoken inputs was required for semantic processing, or if a degree of automatic processing occurs when the focus of attention is directed elsewhere? High-density ERPs were acquired from twenty-two adolescents (12-17 years), under two experimental conditions: 1. individuals actively determined whether the final word in a sentence was congruent or incongruent with sentence context, or 2. passively listened to background sentences while watching a video. When sentences were ignored, N400 and LPC/P600 were robustly evoked to semantic errors, albeit with reduced amplitudes and protracted/delayed latencies. Statistically distinct topographic distributions during passive versus active paradigms pointed to distinct generator configurations for semantic processing as a function of attention. Covert semantic processing continues in neurotypical adolescents when explicit attention is withdrawn from sentence inputs. As such, this approach could be used to objectively investigate semantic processing in populations with communication deficits.
语言理解需要对单个单词及其在句子中的上下文进行语义处理。特征明确的事件相关电位 (ERP) 成分（N400 和晚期正性成分 (LPC/P600)）为语义处理提供了神经标志物，并且当在句子中引入语义错误时，它们会被强烈激发。这些措施可用于评估临床人群的语义处理，但尚不清楚它们是否可以在更严重的神经发育障碍中激发，在这些障碍中，无法客观评估对句子输入的明确关注（即，当句子被动收听时）。我们评估了在明确忽略句子输入的青少年中是否可以检测到 N400 和 LPC/P600。具体来说，研究了是否需要明确关注口语输入来进行语义处理，或者当注意力集中在其他地方时是否会发生一定程度的自动处理？从二十二名青少年（12-17 岁）中获取了高密度 ERP，在两种实验条件下：1. 个体主动确定句子末尾的单词是否与句子上下文一致或不一致，或者 2. 被动收听背景句子，同时观看视频。当句子被忽略时，即使幅度减小且潜伏期延长/延迟，N400 和 LPC/P600 仍会强烈激发语义错误。在被动与主动范式之间具有统计学上不同的拓扑分布，这表明注意力作为语义处理的功能存在不同的发生器配置。当从句子输入中撤回明确关注时，神经典型青少年仍会进行隐蔽的语义处理。因此，这种方法可用于客观研究具有沟通障碍的人群中的语义处理。
