Tuning diversity in the functional microarchitecture of visual cortex

描述（由申请人提供）：在大型哺乳动物的初级视觉皮层（V1）中，内在信号光学成像已经证明了调谐偏好的连续地形图。正如对有效神经代码的预期，不同刺激参数的映射往往重叠，使得它们的轮廓彼此垂直。然而，最终的编码效率取决于在精细的空间尺度上的调谐偏好和调谐形状的组织，这需要具有微观分辨率的功能测量。在这里，我们建议使用双光子成像猕猴VI的特点调谐多样性内的所谓的超柱，并衡量其理论后果的整体人口代码。通过双光子成像，我们可以在数百微米宽的皮层上逐个细胞地测量多个刺激特性的调谐曲线。目的1是研究每个细胞的调谐形状和相邻的人口之间的关系的调谐曲线。实验和分析将帮助我们更好地理解皮层如何执行影响单个神经元调谐特性的局部计算。在目标2中，我们将测试调优多样性对超列中信息内容的影响。的分析是针对寻找可能的好处，有神经元嵌入在连续的功能地图传输信息的视觉场景到下游皮层区域。在目标3中，我们将研究一个相关问题。我们假设，皮层超柱是不完美的刺激属性的覆盖范围，这是抵消调谐带宽的变化。总的来说，本提案中的实验和分析旨在使用强大的新技术解决感觉系统神经科学中的基本问题。公共卫生相关性：我们期望获得有关皮层回路如何整合感觉输入的知识，以便信息可以忠实地传递到更高级别的区域，以创造正常的行为。许多神经系统疾病，如自闭症，注意力缺陷障碍（ADD），癫痫和精神分裂症，知之甚少。关于正常皮质功能的知识，如基本的布线规则和皮质功能的组织，是我们理解异常皮质活动的基础。

DESCRIPTION (provided by applicant): In primary visual cortex (V1) of large mammals, intrinsic signal optical imaging has demonstrated continuous topographic maps of tuning preference. As expected for an efficient neural code, the maps of different stimulus parameters tend to overlap such that their contours run perpendicular to each other. However, the ultimate coding efficiency is dependent on the organization of both tuning preference and tuning shape at a fine spatial scale, which requires functional measurements with microscopic resolution. Here, we propose the use of two-photon imaging in macaque VI to characterize tuning diversity within the so-called hypercolumn and to measure its theoretical consequences on the overall population code. With two-photon imaging, we can measure tuning curves of multiple stimulus properties on a cell-by-cell basis across a patch of cortex that is hundreds of microns wide. Aim 1 is to investigate relationships between each cell's tuning shape and the neighboring population of tuning curves. The experiments and analyses will help us to better understand how the cortex performs local computations that affect the tuning properties of individual neurons. In Aim 2, we will test the impact of tuning diversity on information content within the hypercolumn. The analyses are directed toward finding possible benefits of having neurons embedded in continuous functional maps for transmitting information about the visual scene to downstream cortical areas. In Aim 3, we will examine a related issue. We hypothesize that the cortical hypercolumn is not perfect in its coverage of stimulus properties and that this is counterbalanced by changes in tuning bandwidth. Overall, the experiments and analyses in this proposal are designed to address fundamental questions in sensory systems neuroscience using a powerful new technique. PUBLIC HEALTH RELEVANCE: We expect to acquire knowledge on how cortical circuits integrate sensory input so that the information can be faithfully passed on to higher level areas to create normal behavior. Many neurological disorders such as autism, attention deficit disorder (ADD), epilepsy, and schizophrenia, are poorly understood. Knowledge about normal cortical function such as basic wiring rules and the organization of functionality in the cortex is fundamental to our understanding of abnormal cortical activity.