维持注意与选择注意具有不同的脑机制：来自事件相关电位的证据

摘要

背景：目前，学者们对注意的研究主要集中于注意与其他心理现象之间的关系，而对注意自身的不同类型，如维持注意与选择注意之间的比较，却较少研究。目的：维持注意与选择注意作为两种不同的注意类型，在认知加工中的作用明显不同，探讨它们是否具有不同的脑机制。方法：随机选取18名大学生，男女各半，测量他们在进行两种注意任务时的事件相关电位。实验程序用E-Prime编写并在计算机上呈现，实验任务由Karl等人的实验范式修改而来，包括选择注意测试流程和维持注意测试流程。呈现注视点500 ms，然后随机出现3个并排的图形，呈现时间为300 ms。要求受试者按要求尽可能快速而准确的做出反应。结果与结论：表明2种注意具有不同的认知神经机制：维持注意与选择注意在时间进程及波峰和潜伏期方面都存在显著差异。维持注意所诱发的脑电波在脑区分布上更广泛，以正波为主，而选择注意所诱发的脑电波由正波和负波2种；维持注意诱发出更大的N100和N250成分，但在中期阶段，选择注意诱发的P180波要大。这可能表明对事物的选择出现在任务的中期阶段；两种注意任务所诱发的事件相关电位在头皮前后发生逆转现象，很可能是所有注意都具有的特性。%BACKGROUND:At present, researches about attention mainly concentrate on the relationship between attention and other psychological phenomena, but studies concerning different types of attention itself (sustained attention versus selective attention) are few. OBJECTIVE:To investigate the brain mechanisms of sustained and selective attentions which have different roles in the cognitive process. METHODS:Event-related potentials (ERPs) were measured when 18 col ege students’ participants (half male and half female) were performing selective and sustained attention tasks. The program was written in E-Prime and displayed on a computer, and the experimental task was adapted from Karl et al. reported experimental paradigm, including selective attention and sustained attention tasks. The time of fixation point given was 500 ms, and the time of three randomly abreast pictures given was 300 ms. Al the participants were asked to make rapid and accurate response as much as possible. RESULTS AND CONCLUSION:The ERPs elicited by the two attention tasks were different in the aspects of time process, wave crest and latency. The brain regions activated by the sustained attention were wider than those by selective attention. The ERPs elicited by the sustained attention mainly presents as positive waves, whereas those elicited by the selective attention were reflected as both positive and negative waves. The EPRs elicited by the sustained attention were N100 and N250, but in the metaphase, selective attention elicited the P180. These may indicate that event choice appears in the middle stage of the task. Besides, the reversion of EPRs elicited by the two attention tasks in the anterior and posterior scalp is likely to be a generality of al attentions.