Deco Gustavo, Pollatos Olga, Zihl Josef
Siemens AG, Corporate Technology, CT IC 4, Munich, Germany.
Vision Res. 2002 Dec;42(27):2925-45. doi: 10.1016/s0042-6989(02)00358-9.
Historically, the psychophysical evidence for "selective attention" originated mainly from visual search experiments. A first important distinction in the processing of information in visual search tasks is its separation in two stages. The first, early "preattentive" stage operates in parallel across the entire visual field extracting single "primitive features" without integrating them. The second "attentive" stage corresponds to the specialized integration of information from a limited part of the field at any one time, i.e. serially. So far, models based on the above mentioned two-stage processes have been able to distinguish features from conjunction search conditions based on the observed slopes of the linear relation between reaction time (i.e., search time) and the number of items in the stimulus array. We propose a neuroscience based model for visual attention that works across the visual field in parallel, but due to its intrinsic dynamics can show the two experimentally observed modes of visual attention, namely: the serial focal attention and the parallel spread of attention over space. The model demonstrates that neither explicit serial focal search nor saliency maps need to be assumed. In the present model the focus of attention is not included in the system but only emerges after convergence of the dynamical behaviour of the neural networks. Furthermore, existing models have not been able to explain the variation of slopes observed in different kinds of conjunction search modes. We hypothesize that the different slopes can be explained by assuming that selective attention is guided by an independent mechanism which corresponds to the independent search for each feature. The model consistently integrates the different neuroscience levels by considering the microscopic neurodynamical mechanism that underlies visual attention, the different brain areas of the dorsal or "where" and ventral or "what" paths of the visual cortex, and behavioural data.
从历史上看，“选择性注意”的心理物理学证据主要源自视觉搜索实验。视觉搜索任务中信息处理的一个重要首要区别在于其分为两个阶段。第一个阶段是早期的“前注意”阶段，它在整个视野范围内并行运作，提取单个“原始特征”而不进行整合。第二个“注意”阶段则对应于在任何时刻对来自视野有限部分的信息进行专门整合，即串行整合。到目前为止，基于上述两阶段过程的模型能够根据观察到的反应时间（即搜索时间）与刺激阵列中项目数量之间线性关系的斜率，区分特征搜索条件和联合搜索条件。我们提出了一种基于神经科学的视觉注意模型，该模型在整个视野范围内并行运作，但由于其内在动力学特性，能够展现出两种实验观察到的视觉注意模式，即：串行焦点注意和注意力在空间上的并行扩散。该模型表明，既不需要假设明确的串行焦点搜索，也不需要假设显著性图。在当前模型中，注意焦点并不包含在系统中，而是仅在神经网络动力学行为收敛后才出现。此外，现有模型一直无法解释在不同类型联合搜索模式中观察到的斜率变化。我们假设，通过假定选择性注意由一种独立机制引导，该机制对应于对每个特征的独立搜索，可以解释不同的斜率。该模型通过考虑构成视觉注意基础的微观神经动力学机制、视觉皮层背侧或“哪里”以及腹侧或“什么”路径的不同脑区以及行为数据，始终如一地整合了不同的神经科学层面。
