视觉空间注意的早期ERP等级效应

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 16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位于枕部结论下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。

Early Scale Effects of the Visual Spatial Attention

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 P1, and N1, 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.