Neural Basis of Shape from Texture

描述（由申请人提供）：这个项目的目的是了解图案表面的三维形状感知。纹状外皮层包括许多神经元，这些神经元对纹理线索定义的三维表面方向有选择性，但没有可行的神经连接模型来建立这样的接受野。我们已经证明，从纹理中提取三维形状，不需要假设纹理均匀性和估计纹理梯度。相反，表面曲率/方向估计是由方向流提供的，深度估计是由频率流提供的。这些流动预测了正确的认知和错误的认知。由于V1神经元对方向和频率有选择性，我们将建立模型，结合它们的输出来提取方向和频率流，以识别不同的形状特征。实验将明确神经机制的时空特性。我们将使用新的诊断刺激类型，没有线索冲突，来检查运动和纹理线索在3-D感知中相互作用的方式，以及运动是否有助于感知内在曲率或仅仅是相对深度。我们将根据方向流和频率梯度来分析自然纹理对象上的阴影模式。我们将看到这些方面的阴影是如何在3d感知中相互作用的，从纹理的方向和频率信息。我们将研究纹理和轮廓线索如何相互作用，以解释一些运动和形状幻象与真实的三维固体。我们将通过使用触觉反馈来纠正来自纹理线索的误解，来测试来自纹理的形状的神经机制是硬连线还是可以通过经验改变。这项研究将展示简单的神经连接如何导致复杂的3d感知。这些结果将有助于理解形状感知神经缺陷的原因，并为有这种缺陷的患者建立人工视觉辅助工具。

DESCRIPTION (provided by applicant): The aim of this project is to understand the three-dimensional shape perception of patterned surfaces. Extra-striate cortex includes many neurons that are selective to 3-D surface orientation defined by texture cues, but there are no feasible models of neural connections that build such receptive fields. We have shown that to extract 3-D shape from texture, assumptions of texture homogeneity and estimates of texture gradients are not needed. Instead, surface curvature/orientation estimates are provided by orientation flows, and depth estimates by frequency flows. These flows predict both correct perceptions and misperceptions. Since V1 neurons are selective for orientation and frequency, we will build models that combine their outputs to extract orientation and frequency flows for identifying distinct shape features. Experiments will specify the temporal and spatial properties of the neural mechanisms. We will use new types of diagnostic stimuli, without cue conflict, to examine the manner in which motion and texture cues interact in 3-D perception, and whether motion contributes to the perception of intrinsic curvature or just to relative depth. We will analyze shading patterns on naturalistic textured objects in terms of orientation flows and frequency gradients. We will see how these aspects of shading interact in 3-D perception, with orientation and frequency information from textures. We will examine how texture and silhouette cues interact to explain some motion and shape illusions with real 3-D solids. We will test whether neural mechanisms for shape-from texture are hard-wired or can be altered by experience, by using haptic feedback to correct misperceptions from texture cues. This study will show how simple neural connections lead to complex 3-D percepts. These results will be useful both in understanding the causes of neurological deficits in shape perception, and in building artificial visual aids for patients with such deficits.