Functional connectivity in primary visual cortex

描述（由申请人提供）：人类的大脑需要访问一个精确的视觉空间地图来解释我们所看到的图像。最准确和完整的视觉地图位于初级视觉皮层，所有的基本刺激特性被认为是系统地表示，包括空间位置，方向和相位。例如，这个页面中间的一个垂直的暗条可以在初级视觉皮层中通过它的位置（注视点）、方向（垂直）和相位（暗边有光）来表示。虽然先前的研究在我们理解空间位置和方向是如何在初级视觉皮层上映射的方面取得了重要进展，但我们仍然不知道空间相位是如何在这张地图上表示的。鉴于相位在图像处理算法中的重要性，这是一个基本的知识缺口，图像处理算法通常应用于卫星图像、医学成像、视频电话和字符识别。目前的实验数据表明，空间相位在整个皮层中是随机分布的；然而，计算模型坚持认为相位应该聚集在皮层地图的特定区域。我们最近的研究结果首次证明了空间相位明显簇的存在，这与皮层中刺激取向的映射密切相关。此外，我们还表明，暗占主导的相比光占主导的相更能表现出来。本研究项目的主要目标是研究这些新发现的皮层空间相位图的组织，该方法利用了多电极记录的最新进展，并且比过去使用的其他方法具有更好的时空分辨率。通过我们的多电极方法，我们将揭示视觉皮层地图的空间位置、方向和相位的相互关联的组织，这些地图中暗优势的地形，以及在每100 x 100微米的皮层内控制多个刺激维度表征的规则。我们将使用这些测量来建立一个详细的数据库，该数据库包含刺激特征在视觉皮层地图上的多维映射，并测试当前皮层功能结构和皮层发育的计算模型。

DESCRIPTION (provided by applicant): The human brain needs to have access to an accurate map of visual space to interpret the images that we see. The most accurate and complete visual map is located in primary visual cortex, where all the basic stimulus properties are thought to be systematically represented, including spatial location, orientation and phase. For example, a vertical dark bar in the middle of this page can be represented in primary visual cortex by its position (point of fixation), orientation (vertical) and phase (dark flanked by light. While previous studies have made important advances in our understanding of how spatial location and orientation are mapped across the primary visual cortex, we still do not know how spatial phase is represented in this map. This is a fundamental gap in knowledge given the importance that phase has in image processing algorithms, which are regularly applied to satellite imagery, medical imaging, videophone and character recognition. Current experimental data suggest that spatial phase is randomly distributed throughout the cortex; however, computational models keep insisting that phase should be clustered in specific regions of the cortical map. Our recent results demonstrate, for the first time, the existence of pronounced clusters for spatial phase that are closely related to the mapping of stimulus orientation in cortex. In addition, we show that dark-dominated phases are better represented than light-dominated ones. The main goal of this research project is to study the organization of these newly discovered cortical maps for spatial phase with a novel approach that takes advantage of recent advances in multielectrode recording and has considerably better spatio-temporal resolution than other methods used in the past. With our multielectrode approach, we will reveal the inter- related organization of visual cortical maps for spatial position, orientation and phase the topography of dark- dominance in these maps and the rules that govern the representation of multiple stimulus dimensions within each 100 x 100 microns of cortex. We will use these measurements to build a detailed database of the multi- dimensional mapping of stimulus features across the visual cortical map and to test current computational models of functional cortical architecture and cortical development.