Queensland Brain Institute, The University of Queensland, Brisbane, Queensland, Australia.
Neuroimage. 2012 Jul 16;61(4):1050-8. doi: 10.1016/j.neuroimage.2012.03.040. Epub 2012 Mar 20.
Mechanisms of attention are required to prioritise goal-relevant sensory events under conditions of stimulus competition. According to the perceptual load model of attention, the extent to which task-irrelevant inputs are processed is determined by the relative demands of discriminating the target: the more perceptually demanding the target task, the less unattended stimuli will be processed. Although much evidence supports the perceptual load model for competing stimuli within a single sensory modality, the effects of perceptual load in one modality on distractor processing in another is less clear. Here we used steady-state evoked potentials (SSEPs) to measure neural responses to irrelevant visual checkerboard stimuli while participants performed either a visual or auditory task that varied in perceptual load. Consistent with perceptual load theory, increasing visual task load suppressed SSEPs to the ignored visual checkerboards. In contrast, increasing auditory task load enhanced SSEPs to the ignored visual checkerboards. This enhanced neural response to irrelevant visual stimuli under auditory load suggests that exhausting capacity within one modality selectively compromises inhibitory processes required for filtering stimuli in another.
注意机制是在刺激竞争的条件下优先处理与目标相关的感觉事件所必需的。根据注意的知觉负载模型，对任务无关输入的处理程度取决于区分目标的相对要求：目标任务的感知要求越高，未被注意的刺激就越少被处理。尽管有大量证据支持单一感觉模态中竞争刺激的知觉负载模型，但知觉负载在一种模态中对另一种模态中的分心处理的影响却不太清楚。在这里，我们使用稳态诱发电位（SSEP）来测量参与者在执行视觉或听觉任务时对无关视觉棋盘刺激的神经反应，这些任务在知觉负载上有所不同。与知觉负载理论一致，增加视觉任务负载会抑制对忽略的视觉棋盘的 SSEP。相比之下，增加听觉任务负载会增强对忽略的视觉棋盘的 SSEP。在听觉负载下对无关视觉刺激的增强的神经反应表明，在一种模态中耗尽容量会选择性地损害另一种模态中过滤刺激所需的抑制过程。
