Berti Stefan
Department of Psychology, Johannes Gutenberg-University Mainz, Staudinger Weg 9, D-55099 Mainz, Germany.
Neurosci Lett. 2008 Mar 28;434(2):200-5. doi: 10.1016/j.neulet.2008.01.055. Epub 2008 Jan 31.
In two experiments applying a memory updating task subjects are asked to perform several arithmetic operations on stored numbers. From a trial-to-trial perspective these operations could be either performed on a previously processed item or on a new item which requires an object switch in working memory. Object switching results in prolonged operation times; these operation time costs reflect the switch of the focus of attention to the relevant information. Event-related brain potentials obtained in object switch trials show an increased P3a around 300 ms and a late, central negative component between 400 ms and 500 ms. The data suggest that the P3a may reflect the unhitching of the focus of attention from the current information or task set through the inhibition of the prepared response while the late negative component may reflect the allocation of the focus of attention to another object in working memory. The present results are best explained within a controlled attention view of working memory supporting the idea that object switching relies on the ability to orient the focus of attention within working memory.
在两项运用记忆更新任务的实验中，要求受试者对存储的数字进行若干算术运算。从逐次试验的角度来看，这些运算既可以在先前处理过的项目上进行，也可以在需要工作记忆中进行对象切换的新项目上进行。对象切换会导致操作时间延长；这些操作时间成本反映了注意力焦点向相关信息的切换。在对象切换试验中获得的事件相关脑电位显示，在约300毫秒时P3a增加，在400毫秒至500毫秒之间有一个晚期的中央负成分。数据表明，P3a可能反映了通过抑制准备好的反应，注意力焦点从当前信息或任务集上的解除，而晚期负成分可能反映了注意力焦点在工作记忆中分配到另一个对象上。目前的结果在工作记忆的控制性注意观点内得到了最好的解释，支持了对象切换依赖于在工作记忆中定向注意力焦点能力的观点。
