不同提示条件下视空间注意的事件相关电位研究

目的：采用“提示-目标”的视觉实验范式,分别以汉字和范围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：背景由三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。指定“T”为靶刺激,大提示时,目标“T”可能会出现在大中小三个圈内;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：汉字提示的反应时明显长于范围提示：同时与范围提示相比,汉字提示下的靶刺激引起后部P1的增强和N1的抑制以及P2的增强。结论：范围提示能够加快靶刺激识别或视觉搜索的速度,汉字提示时启动的是内源性注意系统,在早期感知阶段,前额叶资源的利用不够完善,证明了汉字提示与范围提示具有不同的加工机制．

A study on event-related potential of visual attention under different cue

Objective: To investigate the visual attention mechanisms of brain through ERP technique by using the "cue-target" experimental paradigm, and the attended range were cued by different Chinese characters cue or region cue; the visual attention mechanisms of brain were investigated through ERP technique. Method:16 healthy young participants were involved. The stimulus trail included "background-cue-target". The background was comprised of three homocentric white circles. 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" maybe appeared within the three circles. When the cue was medium, the T maybe 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 under Chinese character cues was much longer than that under range cues. Compared with that in region cue, target stimulation in Chinese character cue could lead to the increase of posterior P1, the decrease of N1 and the increase of P2. Conclusion: Region cue can make target discrimination faster; Therefore, as a kind of interior cue, the system of interior cue is started under Chinese characters as cues. At the early stage of perception, very few neurons are inactivated, and the use of prefrontal area resources is not enough.These findings indicate that range cues and Chinese characters as cues have different early processing mechanisms.