Smid H G, Heinze H J
Department of Clinical Neurophysiology, Medizinische Fakultät, Otto-von-Guericke University, Magdeburg, Germany.
Biol Psychol. 1997 Jan 31;44(3):161-85. doi: 10.1016/s0301-0511(96)05216-7.
We examined the functional and temporal organization of task-directed selective processing of the color and shape of alphanumeric characters. Dependent variables were measures derived from event-related brain potentials (onset latency of selection negativity (SN) and the lateralized readiness potential). We found SNs related to the relevance for correct task-performance of the color, the global shape and the local shape of the characters. The onset latencies of these SNs suggested that color and global shape were identified at the same time and earlier than local shape. The absence of an SN to global shape if the color was irrelevant suggested that selection on the basis of the global shape depended hierarchically on that of color. Selection of the local shape was independent of color relevance. The lateralized readiness potentials suggested that response selection occurred when the conjunction of color, global shape and local shape had been identified. No evidence was found for temporal overlap between stimulus identification and response selection. These findings show that selective task-directed processing can be studied at multiple levels in a single paradigm. They are inconsistent with the central assumption of several continuous information transmission models that relevant partial information is used to activate associated responses as soon as it becomes available.
我们研究了字母数字字符颜色和形状的任务导向性选择性加工的功能和时间组织。因变量是从事件相关脑电位得出的测量值（选择负波（SN）的起始潜伏期和偏侧化准备电位）。我们发现SN与字符颜色、整体形状和局部形状对正确任务表现的相关性有关。这些SN的起始潜伏期表明，颜色和整体形状是同时被识别的，且早于局部形状。如果颜色不相关，则不存在与整体形状相关的SN，这表明基于整体形状的选择在层次上依赖于颜色选择。局部形状的选择与颜色相关性无关。偏侧化准备电位表明，当颜色、整体形状和局部形状的结合被识别时，反应选择就会发生。未发现刺激识别和反应选择之间存在时间重叠的证据。这些发现表明，在单一范式中可以在多个层面研究任务导向性选择性加工。它们与几种连续信息传递模型的核心假设不一致，这些模型认为，相关的部分信息一旦可用，就会被用来激活相关反应。
