摘要
Stroop效应能够反映大脑对冲突干扰的注意.为了深入分析Stroop效应中大脑的认知活动过程,设计了稳态视觉诱发电位（SSVEP）背景标记的Stroop实验范式,记录同时含有事件相关电位（ERP）信号和SSVEP信号的脑电信号,并提出基于Hermite滤波器的脑电信号包络分析方法.采集了10例受试的脑电数据,分离得到ERP信号和SSVEP信号.在刺激后400 ～ 600 ms时间窗内,不一致条件的ERP信号比一致条件的ERP信号更负.条件之间的差异具有统计显著性,差异主要分布在前额区域,可视为Stroop效应在脑电上的体现.通过包络分析发现,SSVEP信号的包络在刺激后存在明显的下降过程.ERP信号Alpha频带总包络刺激之后的变化与其刺激之前的水平有关,若刺激之前Alpha频带总包络的水平较高,刺激之后包络先小幅上升后下降到比刺激前更低的水平；若刺激之前水平较低,刺激之后的包络上升后下降到与刺激前相当的水平.通过SSVEP背景标记Stroop实验范式和包络分析,可进一步研究Stroop效应的认知活动过程,也可为其他认知实验提供参照.
Stroop effect can reflect the brain attention of the conflict and the interference. In order to analyze the brain cognitive activity of Stroop effect deeply, the Stroop experiment paradigm marked with steady state visual evoked potential （SSVEP） background was designed innovatively, which can get EEG data including both the event related potential （ERP） signals and the SSVEP signals. To realize this, the envelope analysis method based on Hermite filters was proposed. EEG data of ten subjects were recorded, and then the ERP signals and SSVEP signals were gotten respectively. In the time window of 400 ~ 600 ms after stimulus, the ERP signal of incongruent condition was more negative than that of congruent condition. The difference between two conditions was significant statistically and mainly distributed in the prefrontal regions, which was the EEG reflection of the Stroop effect. Through the envelope analysis, it was found that the envelope of SSVEP signal declined remarkably after the stimulus. The poststimulus changes of the Alpha frequency band total envelope of the ERP signal were related with its prestimulus level. If its level before stimulus was high, it declined to the lower level after a small increase; if its level before stimulus was low, it remained to the same level after an increase. We got the further cognitive activity study of Stroop effect through the Stroop experiment paradigm marked with SSVEP background and the envelope analysis method, which also provides a reference for other cognitive experiments.
出处
《中国生物医学工程学报》
CAS
CSCD
北大核心
2014年第1期1-7,共7页
Chinese Journal of Biomedical Engineering
基金
国家自然科学基金重点项目(91120007)
国家高技术研究发展计划(863计划)(2012AA011601)
