Electrophysiological responses of relatedness to consecutive word stimuli in relation to an actively recollected target word

In this study, we investigate the robustness of electrophysiological responses of relatedness to multiple consecutive word stimuli (probes), in relation to an actively recollected target word. Such relatedness information could be used by a Brain Computer Interface to infer the active semantic concept on a user’s mind, by integrating the knowledge of the relationship between the multiple probe words and the `unknown' target. Such a BCI can take advantage of the N400: an event related potential that is sensitive to semantic content of a stimulus in relation to an established semantic context. However, it is unknown whether the N400 is suited for the multiple probing paradigm we propose, as other intervening words might distract from the established context (i.e., the target word). We perform an experiment in which we present up to ten words after an initial target word, in order to investigate whether the strength of the N400 attenuates for later probes.

本研究旨在探究：相较于主动回忆的目标单词，与多个连续单词刺激（探测刺激）相关的关联性电生理反应的稳健性。此类关联性信息可被脑机接口（Brain Computer Interface, BCI）所利用，通过整合多个探测单词与“未知”目标单词之间的关联知识，推断用户脑中的活跃语义概念。此类脑机接口可借助N400成分——一种对刺激语义内容与既定语义情境间的关联具有敏感性的事件相关电位。然而，目前尚不明确N400是否适用于我们提出的多探测范式，因为其间插入的其他单词可能会干扰既定的语义情境（即目标单词）。为此我们开展了一项实验：在初始目标单词后呈现至多10个后续单词，以此探究N400的响应强度是否会随后续探测刺激的呈现而衰减。