Deco Gustavo, Rolls Edmund T
Siemens AG, Corporate Technology, Computational Neuroscience, CT IC 4, D-81730 Munich, Germany.
Eur J Neurosci. 2002 Nov;16(10):1994-2000. doi: 10.1046/j.1460-9568.2002.02279.x.
Some patients with damage to the right parietal cortex show neglect for the left half of each of a series of objects shown in a horizontal row in the visual field. The neglect is thus not based on failure to see objects in any part of left visual space, but is object-based. We show that in a model of attention with separate V1, object (inferior temporal cortex, IT) and spatial (posterior parietal cortex, PP) modules the effect can arise after graded damage increasing towards the right of the PP module when the lateral inhibition between neurons in the PP and V1 modules is short-range. The local lateral inhibition produces high contrast effects at the edges of each object, and it is when this interacts with gradually increasing damage through the left visual field that the visibility of the left half of each object is especially impaired. This result was found in a formal model completely specified by mean field equations to quantify the dynamical interactions between the modules. This is the first quantitative account of object-based neglect found in humans with right parietal cortex damage, and provides evidence that the model of attention we describe can account for even detailed and extraordinary phenomena that can occur in visual perception.
一些右侧顶叶皮层受损的患者会忽视视野中水平排列的一系列物体的左半部分。因此，这种忽视并非基于未能看到左半侧视野中任何位置的物体，而是基于物体本身。我们表明，在一个具有独立的初级视觉皮层（V1）、物体（颞下皮层，IT）和空间（后顶叶皮层，PP）模块的注意力模型中，当PP模块和V1模块中的神经元之间的侧向抑制为短程时，随着向PP模块右侧逐渐增加的分级损伤，这种效应就会出现。局部侧向抑制在每个物体的边缘产生高对比度效应，而正是当这种效应与通过左半侧视野逐渐增加的损伤相互作用时，每个物体左半部分的可见性才会特别受损。这一结果是在一个由平均场方程完全确定的形式模型中发现的，该模型用于量化各模块之间的动态相互作用。这是对右侧顶叶皮层受损患者中基于物体的忽视现象的首次定量解释，并提供了证据表明我们所描述的注意力模型能够解释视觉感知中可能出现的甚至是详细而特殊的现象。
