University of California, San Diego.
J Cogn Neurosci. 1993 Spring;5(2):188-95. doi: 10.1162/jocn.1993.5.2.188.
Abstract When subjects are explicitly cued to focus attention on a particular location in visual space, targets presented at that location have been shown to elicit enhanced sensory-evoked activity in recordings of event-related brain potentials (ERPs). The present study sought to determine if this type of sensory facilitation also occurs during visual search tasks in which a feature conjunction target must be identified, presumably by means of focal attention, within an array of distractor items. In this experiment, subjects were required to discriminate the shape of a distinctively colored target item within an array containing 15 distractor items, and ERPs were elicited by task-irrelevant probe stimuli that were presented at the location of the target item or at the location of a distractor item on the opposite side of the array. When the delay between search-array onset and probe onset was 250 msec, the sensory-evoked responses in the latency range 75-200 msec were larger for probes presented at the location of the target than for probes presented at the location of the irrelevant distractor. These results indicate that sensory processing is modulated in a spatially restricted manner during visual search, and that focusing attention on a feature conjunction target engages neural systems that are shared with other forms of visual-spatial attention.
摘要 当被试被明确提示将注意力集中在视觉空间的特定位置时，与该位置相关的目标会在事件相关脑电位（ERP）的记录中引起增强的感觉诱发电活动。本研究旨在确定在视觉搜索任务中是否也会发生这种类型的感觉促进，在这种任务中，必须通过焦点注意来识别特征结合目标，该目标通常存在于一组分心项目中。在该实验中，要求被试在包含 15 个分心项的数组中辨别出具有独特颜色的目标项的形状，通过与任务无关的探测刺激来引发 ERP，这些刺激分别呈现于目标项的位置或数组另一侧的分心项的位置。当搜索数组启动和探测启动之间的延迟为 250 毫秒时，在潜伏期 75-200 毫秒范围内，在目标位置呈现的探测刺激引起的感觉诱发电响应大于在不相关分心位置呈现的探测刺激引起的感觉诱发电响应。这些结果表明，在视觉搜索过程中，感觉处理以空间限制的方式进行调节，并且将注意力集中在特征结合目标上会激活与其他形式的视觉空间注意共享的神经系统。
