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)和视觉皮质中的机制如何分析有关物体的颜色属性的信息，以及这些机制如何决定人类的感知能力。提出了三个紧密联系的生理学研究群体。第一组将通过实验和建模，在LGN和皮质神经元的感受野中建立颜色选择性的潜在组织。这些研究将回答以下问题：感受场的颜色特性在多大程度上是从特定类别的视锥细胞中选择输入，而不是从特定位置的视锥细胞中选择输入；感受野周围的静默区如何塑造神经元的颜色选择性；反之，变化是否会改变神经元的颜色选择性？第二组研究将在大脑皮层神经元中描述感受野的染色特性和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协调相互冲突的要求，即它们的两个感受野具有匹配的空间特性和匹配的颜色特性；另一项研究将揭示双目驱动的神经元如何结合两只眼睛中产生的不同颜色信号。这些研究是理解双目混色的核心。第三组研究将描述颜色适应的机制，这些机制深刻地影响颜色敏感性和外观。一项研究将分析LGN神经元中表达的早期信号转换，这些转换是由适应平均色度带来的；另一项研究将分析皮质中随后发生的转换--既包括适应平均色度带来的转换，也包括适应色度对比度带来的转换。

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.