P3, positive slow wave and working memory load:: a study on the functional correlates of slow wave activity
P3, positive slow wave and working memory load:: a study on the functional correlates of slow wave activity
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DOI：
10.1016/s0168-5597(97)00085-3
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发表时间：
1998-04-01
期刊：
影响因子：
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通讯作者：
Cézanne-Bert, G
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文献类型：
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作者：
García-Larrea, L;Cézanne-Bert, G
众所周知，每当目标检测导致复杂的辅助任务时，P300 之后就会出现“慢波”类型的顶叶积极性。尽管这些“正慢波”（PSW）的功能相关性尚不清楚，但有人建议它们可以索引（a）选择或决策过程，（b）响应的准备或（c）对其正确性的评估。我们研究了 PSW 是否可以通过缺乏运动组件且需要很长反应时间的范式与这些假定的信息处理步骤分离。在我们的协议中，目标刺激充当触发信号，默默地执行 4 种不同任务之一，即（a）目标计数的简单更新； (b) 以三为一组倒数； (c) 同时更新两个项目（星期几和月份序号）和 (d) 更新 3 个项目（以上两项加上一年中的月份）。在不同的实验中获得了 5 名受试者对相同刺激的反应时间。不同的任务不会改变 N2 或 P3b 分量的延迟，但会减弱 P3 的幅度，作为主观难度分数的镜像。在必须更新两个或三个项目的情况下，会出现明显的顶叶 PSW。该 PSW 比相同实验的反应时间早 1-2 秒，因此可以与选择和决策过程分离。 PSW 延迟与要更新的项目数量相关，但与主观难度无关。在目前的范式中，PSW 似乎索引了从工作记忆中检索信息；然而，一般而言，我们的结果表明 PSW 是一种非特定活动，它发出目标检测后立即完成任何同步操作的信号。我们的数据表明 P3 和 PSW 之间存在功能联系，这也得到了它们各自头皮地形的相似性的支持。事实证明，本范式易于实现，并且适合研究在执行多个任务期间控制注意力和工作记忆控制的“执行”功能。 (C) 1998 爱思唯尔科学爱尔兰有限公司
Parietal positivities of the 'slow wave' type are known to emerge after the P300 whenever target detection leads to a complex subsidiary task. Although the functional correlates of these 'positive slow waves' (PSW) are not known, it has been suggested that they may index (a) the selection or decision processes, (b) the preparation of the response or (c) the evaluation of its correctness. We investigated whether PSW could be dissociated from each of these putative steps of information processing by means of a paradigm devoid of motor components and needing very long reaction times. In our protocol, target stimuli acted as the triggering signal to perform silently one of 4 different tasks, namely (a) simple updating of a target count; (b) counting backward in threes; (c) simultaneous updating of two items (day of the week and ordinal of the month) and (d) updating of 3 items (the two above plus the month of the year). Reaction times to the same stimuli were obtained in 5 subjects during separate sessions. The different tasks did not modify the latencies of N2 or P3b components, but attenuated the amplitude of P3 as a mirror image of the subjective difficulty scores. A conspicuous parietal PSW appeared in conditions where two or 3 items had to be updated. This PSW developed 1-2 s earlier than the reaction times to the same experiments and could be therefore dissociated from the selection and decision processes. PSW latency was correlated with the number of items to be updated, but not with subjective difficulty. In the present paradigm PSW appeared to index the retrieval of information from working memory; however, in mon general terms our results suggest that PSW is a non-specific activity that signals the completion of any synchronized operation immediately following target detection. Our data suggest a functional link between P3 and PSW, also supported by the similarity of their respective scalp topographies. The present paradigm proved to be easy to implement and suitable to study the 'executive' functions governing attentional and working-memory control during the performance of multiple tasks. (C) 1998 Elsevier Science Ireland Ltd.