Quantitative Studies of Visual Pathways

描述（由申请人提供）：总体目标是了解外侧膝状核（LGN）和视觉皮层中的机制如何分析物体的颜色属性信息，以及这些机制如何决定人类的感知能力。提出了三组密切相关的生理研究。第一组将通过实验和建模，建立LGN和皮层神经元接受野中颜色选择性的潜在组织。这些研究将回答以下问题：选择特定类别的视锥细胞的输入与选择特定位置的视锥细胞的输入在多大程度上导致了接受野的颜色特性；感受野周围的沉默区如何塑造神经元的颜色选择性；对比度的变化会改变神经元的颜色选择性吗？第二组研究将描述皮层神经元的颜色特性和接受野的双眼特性之间的关系。一项研究将揭示神经元是否以及如何调和它们的两个感受野具有匹配的空间属性和匹配的颜色属性的冲突要求；另一项研究将揭示双眼驱动的神经元如何将两只眼睛中产生的不同颜色信号结合起来。这些研究是理解双眼颜色混合的核心。第三组研究将描述深刻影响颜色敏感性和外观的颜色适应机制。一项研究将分析LGN神经元中表达的早期信号转换，这是由对平均色度的适应所带来的；另一篇文章将分析随后发生在大脑皮层的变化——既包括对平均色度的适应，也包括对色度对比的适应。

DESCRIPTION (provided by applicant): The overall aim is to understand how mechanisms in the lateral geniculate nucleus (LGN) and visual cortex analyze information about the chromatic properties of objects, and how these mechanisms determine human perceptual capabilities. Three closely connected groups of physiological studies are proposed. The first group will establish, through experiment and modeling, the underlying organization of chromatic selectivity in the receptive fields of neurons in LGN and cortex. The studies will answer the following questions: to what extent do the chromatic properties of a receptive field result from selection of inputs from cones of particular classes vs. selection of inputs from cones in particular positions; how does the silent region surrounding the receptive field shape a neuron's chromatic selectivity; do variations in contrast alter the chromatic selectivity of neurons? The second group of studies will characterize in cortical neurons the relationship between the chromatic properties and the binocular properties of receptive fields. One study will reveal whether and how neurons reconcile the conflicting demands that their two receptive fields have matched spatial properties and also matched chromatic properties; another will reveal how binocularly driven neurons combine different color signals arising in the two eyes. These studies are central to understanding binocular color mixture. The third group of studies will characterize mechanisms of chromatic adaptation that profoundly influence color sensitivity and appearance. One study will analyze the early signal transformations, expressed in LGN neurons, that are brought about by adaptation to mean chromaticity; another will analyze the subsequent transformations that occur in cortex--both those brought about by adaptation to the mean chromaticity, and those brought about by adaptation to chromatic contrast.