Multiple scales of representation in V1

 描述(由申请人提供)：初级视觉皮质(V1)可能是研究最好的感觉皮质区域，也是理解皮质处理的广泛原则的模型。同样，V1的定向可能是最简单和研究最充分的皮质感觉特征之一。定向被用作理解其他皮质区域中更复杂的特征加工的模型，定向的V1样感受野在成功的视觉计算模型中起着重要的作用。然而，即使是像V1上的方位图这样基本的东西，人们也理解得不够充分。我们提出了一系列多学科的理论和实证研究，以表征从柱状物的尺度到视网膜定位图的方向选择性。我们将检验这一假设，即定向偏好的粗略偏差是理解V1中定向选择性神经活动与定向知觉之间联系的基础。我们将区分并分别测量三种不同的过程(刺激晕动、基数/径向增益场和非对称环绕抑制)，这些过程可能会导致粗略的方向偏差。这样做将使我们能够表征V1中的基数/径向增益场(即，刺激方向的本征表示)， 独立于边缘效应(来自刺激晕影和环绕抑制)，并确定增益场预测称为倾斜效应的知觉现象的程度。我们将通过量化定向偏好中的细小(即柱状)和中等(即血管聚集)和粗略(即刺激晕影、不对称环绕抑制、基场/径向增益场)比例偏差的相对结构来解决关于刺激定向的fMRI解码的争议。解决来自V1的fMRI测量中方位偏好的来源将指导基于其他大脑区域的多变量统计分析的数千项研究的解释。我们将开发和实现V1中整个神经元群体的响应模型，该模型将能够对所有种类的神经元进行模拟 方法：单个和多个单元的发射率、钙成像、光学成像和功能磁共振反应，实现了它可以在任何刺激图像上运行，包括刺激孔径。在其他应用中，该模型将被用来确定刺激晕动在视觉和视觉神经科学研究中的混乱程度；我们领域的几乎每一项研究都利用了刺激光圈，但忽略了光圈的潜在影响。Variou障碍与视皮层的地形图和功能结构的差异，和/或整个视野的视觉敏感度的差异有关。我们提出的实验方案将很容易适用于患者群体。因此，我们提出的实验方案和理论原则将广泛适用于基础研究和翻译研究。

 DESCRIPTION (provided by applicant): Primary visual cortex (V1) is likely the best studied sensory cortical area, and is a model for understanding broad principles of cortical processing. Similarly, orientation in V1 is likely one of the simplest and best studied cortical sensory features. Orientation is used as a model for understanding more complex feature processing in other cortical areas, and oriented V1-like receptive fields play an important role in successful computational models of vision. Yet even something as basic as the map of orientation on V1 is inadequately understood. We propose a multidisciplinary series of theoretical and empirical studies to characterize orientation selectivity from the scale of columns to that of retinotopic maps. We will test the hypothesis that coarse-scale biases in orientation preferences are fundamental to understanding the link between orientation-selective neural activity in V1 and orientation perception. We will distinguish and separately measure 3 different processes (stimulus vignetting, cardinal/radial gain fields, and asymmetric surround suppression) that might contribute to coarse-scale orientation biases. Doing so will enable us to characterize the cardinal/radial gain fields in V1 (i.e., the intrinsic representation of the stimulus orientation), independent of the edge effects (from stimulus vignetting and surround suppression), and determine the extent to which the gain field predict a perceptual phenomenon called the oblique effect. We will settle the controversy about fMRI decoding of stimulus orientation by quantifying the relative contribu- tions of fine- (i.e., columnar) vs. intermediate- (i.e., vascular pooling) v. coarse (i.e., stimulus vignetting, asymmetric surround suppression, cardinal/radial gain fields) scale biases in orientation preferences. Resolving the source of the orientation preferences in fMRI measurements from V1 will guide the interpretation of thousands of studies based on multivariate statistical analyses in other brain areas. We will develop and implement a model of the responses of an entire population of neurons in V1, that will enable simulations of all variety of methods: single- and multi-unit firing rates, calcium imaging, optical imaging, and fMRI responses, implemented so that it can be run on any stimulus image, including the stimulus aperture. Amongst other applications, the model will be used to establish the extent to which stimulus vignetting is a confound in vision and visual neuroscience research; almost every study in our field utilizes a stimulus aperture, but ignores the potential impact of the aperture. Variou disorders have been associated with differences in the topography and functional architecture of visual cortex, and/or with differences in visual sensitivity across the visual field. The experimental protocols that we propose will be readily applicable to patient populations. Consequently, the experimental protocols and theoretical principles that we propose will be widely applicable in basic as well as translational research.