视觉空间注意的早期ERP等级效应

Early Scale Effects of the Visual Spatial Attention.

目的采用“提示 -目标”的视觉实验范式 ,以文字提示不同等级的搜索范围 ,通过事件相关电位(ERP)技术研究视觉注意脑机制。方法 1 6名在校大学生作为有偿被试 ,刺激序列为背景 -提示 -靶刺激。背景由 3个同心白色圆形线条组成。刺激材料是随机选取的大写英文字母 ,组成大、中、小 3个同心圆圈。提示为汉字“大”“中”和“小” ,指定“T”为靶刺激。大提示时 ,目标”T”可能会出现在大中小 3个圈内 ;中提示时 ,“T”出现在中小两个圈内 ;当小提示时 ,目标只出现在小圈内。结果随着提示等级的减小 ,反应时加快 ,而早期ERP成分P1 与N1 波幅增大 ,偶极子定位发现P1 位于枕部。结论不同的注意范围与早期P1 、N1 成分相关 ,而且提供了支持聚光灯理论的电生理学证据 ,阐明了聚光灯效应发生在信息加工的早期阶段。

Objective To investigate the visual attention mechanisms of brain,the “cue-target” experimental paradigm was adopted, and the attended range was cued by different Chinese characters. Method Sixteen healthy young participants (8 male and 8 female, 19～24 years old with an average of 21) served as the subjects.The stimulus sequence was “background-cue-target”. The background was comprised of three homocentric white circles. Cue was the Chinese character “large”,“median” and “small”. There were 8 capital English letters in each circle, which formed three homocentric circles. “T” was designed as the target stimulus. When the cue was large, the target “T” appeared within the three circles. When the cue was medium,“T” appeared within the medium and small circles. When the cue was small, the T maybe appeared only within the small circle. Result The reaction time became short with the decrease of the cue scale, while P 1 and N 1 components amplitudes increased. Conclusion These results not only provided the electrophysiological evidence for the spot light theory, but also indicated that the spot-light effect happened at the early period of the information processing.