Key Laboratory of Mental Health, Institute of Psychology, Chinese Academy of Sciences, Beijing, China.
Int J Psychophysiol. 2012 Apr;84(1):17-25. doi: 10.1016/j.ijpsycho.2012.01.002. Epub 2012 Jan 14.
The locus of attentional selection is known to vary with perceptual load (Lavie et al., 2004). Under voluntary attention, perceptual load modulates selective visual processing at an early cortical stage, as reflected in the posterior P1 and N1 components of the event-related potentials (ERPs). Adult aging also affects both behavioral and ERP signs of attentional selection. However, it is not known whether perceptual load modulates this relationship. Accordingly, in the present study ERPs were recorded in a voluntary attention task. Young and old participants were asked to discriminate the direction of a target line embedded within a display of four lines that appeared in the left or right visual field. Participants responded faster and more accurately to valid relative to invalid trials and to low-load relative to high-load condition. Older participants responded more slowly and with lower accuracy than young participants in all conditions. The amplitudes of the posterior contralateral P1 and N1 components in valid trials were larger than that in invalid trials in all conditions. N1 amplitude was larger under the high load condition than that in the low load condition. Moreover, in the high perceptual load condition, the old group had a larger N1 than the young group at contralateral sites. The findings suggest that under voluntary attention, perceptual load and aging modulates attentional selection at an early but not the earliest stage, during the N1 (120-200ms) time range. Increased N1 amplitude in older adults may reflect increased demands on target discrimination in high perceptual load.
注意选择的焦点已知会随知觉负载（Lavie 等人，2004 年）而变化。在自愿注意下，知觉负载会在早期皮层阶段调节选择性视觉处理，这反映在事件相关电位（ERP）的后 P1 和 N1 成分中。成人衰老也会影响注意选择的行为和 ERP 迹象。然而，目前尚不清楚知觉负载是否会调节这种关系。因此，在本研究中，在自愿注意任务中记录了 ERP。要求年轻和年长的参与者辨别出目标线的方向，目标线嵌入在显示的四条线中，这些线出现在左或右视野中。与无效试验相比，参与者对有效试验的反应更快、更准确，与高负载条件相比，对低负载条件的反应更快、更准确。在所有条件下，年长参与者的反应速度都比年轻参与者慢，准确性也更低。在有效试验中，与无效试验相比，所有条件下的对侧后 P1 和 N1 成分的振幅都更大。在高负载条件下，N1 振幅大于低负载条件。此外，在高知觉负载条件下，与年轻组相比，老年组在对侧部位的 N1 更大。研究结果表明，在自愿注意下，知觉负载和衰老会在早期而不是最早阶段调节注意选择，即在 N1（120-200ms）时间范围内。在高知觉负载下，年长成年人的 N1 振幅增加可能反映了对目标辨别能力的需求增加。
