位置提示下视觉注意范围的调控机制

THE ADJUST MECHANISM OF VISUAL SPATIAL ATTENTION SCALE ON P2

研究视觉空间注意中不同注意范围引起脑内加工时程的动态变化。使用固定位置的、三种不同直径的线圈作为注意范围的位置性提示 ,祛除空间定位因素的影响 ,记录反应时和事件相关电位 (ERP)数据。结果显示 :在同等注意范围时 ,随着刺激位置远离视野中心 ,反应时延长 ,靶刺激诱发的P1、N1不受刺激位置的影响 ,而其前部N2的波幅明显受到刺激位置的影响 ;在靶刺激位置相同时 ,随着注意范围的扩大 ,反应时缩短 ,靶刺激诱发的P1、N1不受提示范围大小的影响 ,而其前部P2的波幅明显受到注意范围的影响。结果说明 :①视觉注意范围信息加工与靶刺激诱发的P2成分相关 ;②视觉注意诱发的P1、N1成分 ,主要与注意方位相关 ,而与注意范围大小无关 ;③注意范围变化引起注意集中度的调节是在一定范围内进行的。

This study investigated the dynamic brain mechanisms of the visual spatial attention scale under different attention scales. The immobile cues of three different sizes were used to eliminate the effect of the spatial location factor. The simple reaction time (RT) and event-related potentials (ERPs) were recorded. The results were that the RT to the targets under the same cue prolonged when the targets were far away from the center, the target evoked P1 and N1 components were not affected by the target' s location, while the amplitudes of the anterosuperior N2 showed target' s location effect. The RT to the targets in the same location shortened when the cue size was enlarged, the target evoked P1 and N1 were not affected by the attention scale factor, while the amplitudes of the inferoposterior P2 enlarged when the attentive region size enlarged. The results suggested that ① target evoked P2 component was related to the processing of visual scale attention, ② the P1 and N1 components under visual attention were not involved in the attention scale, but related to the attention location processing mainly, ③ the visual scale attention was adjusted to a certain extent.