Rees G, Frith C D
Wellcome Department of Cognitive Neurology, Institute of Neurology, London, UK.
Philos Trans R Soc Lond B Biol Sci. 1998 Aug 29;353(1373):1283-93. doi: 10.1098/rstb.1998.0283.
The selective nature of human perception and action implies a modulatory interaction between sensorimotor processes and attentional processes. This paper explores the use of functional imaging in humans to explore the mechanisms of perceptual selection and the fate of irrelevant stimuli that are not selected. Experiments with positron emission tomography show that two qualitatively different patterns of modulation of cerebral blood flow can be observed in experiments where non-spatial visual attention and auditory attention are manipulated. These patterns of modulation of cerebral blood flow modulation can be described as gain control and bias signal mechanisms. In visual and auditory cortex, the dominant change in cerebral blood flow associated with attention to either modality is related to a bias signal. The relation of these patterns of modulation to attentional effects that have been observed in single neurons is discussed. The existence of mechanisms for selective perception raises the more general question of whether irrelevant ignored stimuli are nevertheless perceived. Lavie's theory of attention proposes that the degree to which ignored stimuli are processed varies depending on the perceptual load of the current task. Evidence from behavioural and functional magnetic resonance imaging studies of ignored visual motion processing is presented in support of this proposal.
人类感知和行动的选择性本质意味着感觉运动过程和注意过程之间存在调节性相互作用。本文探讨了利用人类功能成像来探究知觉选择机制以及未被选择的无关刺激的命运。正电子发射断层扫描实验表明，在操纵非空间视觉注意和听觉注意的实验中，可以观察到两种性质不同的脑血流调节模式。这些脑血流调节模式可被描述为增益控制和偏置信号机制。在视觉和听觉皮层中，与对任何一种模态的注意相关的脑血流的主要变化与偏置信号有关。讨论了这些调节模式与在单个神经元中观察到的注意效应之间的关系。选择性感知机制的存在提出了一个更普遍的问题，即未被注意的无关刺激是否仍被感知。拉维的注意理论提出，被忽视刺激的处理程度取决于当前任务的知觉负荷。本文提供了来自行为和功能磁共振成像研究中关于被忽视视觉运动处理的证据来支持这一观点。
