Wang Yuping, Cui Lili, Wang Huijun, Tian Shujuan, Zhang Xi
Department of Neurology, Xuanwu Hospital, Capital University of Medical Sciences, Beijing 100053, P.R.C.
Psychophysiology. 2004 Jan;41(1):21-9. doi: 10.1111/j.1469-8986.2003.00134.x.
To clarify the brain mechanism for multifeature stimulus comparison, subjects matched the features of two serial visual stimuli in pairs. Stimulus pairs were of four categories: C-S-, color same, shape same (match); C-S+, color same, shape different (shape mismatch); C+S-, color different, shape same (color mismatch); C+S+, color different, shape different (conjunction mismatches). Subjects matched the stimuli in three different sessions according to different attention tasks: attending to color (Ac), attending to shape (As), or attending to both color and shape (Acs). A negative one-peak brain potential, N270, was elicited in all the mismatch conditions with amplitude enhanced in the task-relevant mismatch. Negative potential with two peaks, N270 and N400, appeared when attending to the conjunction mismatches concurrently. The two serial negativities in response to attended feature conjunctions might reflect the temporal different stages for processing conjunction mismatches or conflicts.
为阐明多特征刺激比较的脑机制，受试者对两个连续视觉刺激的特征进行两两匹配。刺激对分为四类：C-S-，颜色相同、形状相同（匹配）；C-S+，颜色相同、形状不同（形状不匹配）；C+S-，颜色不同、形状相同（颜色不匹配）；C+S+，颜色不同、形状不同（联合不匹配）。受试者根据不同的注意力任务在三个不同阶段对刺激进行匹配：关注颜色（Ac）、关注形状（As）或同时关注颜色和形状（Acs）。在所有不匹配条件下均诱发了一个负向单峰脑电，即N270，其波幅在与任务相关的不匹配中增强。当同时关注联合不匹配时，出现了两个负峰的电位，即N270和N400。对所关注特征联合的两个连续负电位可能反映了处理联合不匹配或冲突的不同时间阶段。
