A three-dimensional investigation of the avian thalamofugal visual system –Functional properties, relation to the avian tectofugal system and comparison to the mammalian cortex

鸟类丘脑视觉系统的三维研究“功能特性、与鸟类顶盖系统的关系以及与哺乳动物皮质的比较”

• 批准号: 430157321
• 负责人: Professor Dr. Onur Güntürkün
• 金额: --
• 依托单位: Lehrstuhl für Biopsychologie
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/430157321?language=en
• 关键词: three; dimensional; investigation; avian; thalamofugal

Vision is a central sense for most birds and mammals and consequently the visual systems of both classes show remarkable adaptations and specializations. A commonality is that visual information is processed along two main pathways – the thalamofugal and the tectofugal pathway. However, the division of labor between these pathways varies substantially, not only between the classes but also between the different species of each class. In general, the visual system appears to be highly variable and adaptive making it a prime target for the investigation of the evolutionary optimization of neural processing. In the current application, we will focus on the thalamofugal visual system of the pigeon. Since the majority of our knowledge on the functional properties of this visual pathway stems from owls – an order of visual specialists with advanced adaptations for a nocturnal predatory lifestyle – we aim to investigate the thalamofugal system of the generalist pigeon. Our proposed systematic exploration allows disentangling species-specific adaptations from general features of this processing pathway. In comparison to mammals, there are only few available data on the processing of visual information in the avian thalamofugal pathway. In addition, the studies varied with respect to the methods used. Especially different stimulus sets used hinder a direct comparison. In our first project, we are continuing to perform a three dimensional characterization of the pigeons’ tectofugal visual system. Our results suggest, that the proposed cortex-like anatomy of this visual system is also represented in the physiology of information processing. In the upcoming project, we propose a comparable approach for the thalamofugal visual system. This provides the unique opportunity to compare the contribution of both visual systems – investigated with the same stimuli and methods – to visual processing in pigeons. Beyond the functional characterization of the visual system, the project aims to causally test the computational hierarchy within the thalamofugal pathway using high-density electrophysiology as well as optogenetic manipulations. We will test the hypothesis that the thalamofugal visual system shares anatomical and computational properties with the mammalian cortex. Here our systematic recording of single units, local field potentials and their oscillations as well as an information theoretic approach in cooperation with our colleagues in Göttingen, will give insights into the processing of visual information at different levels. A convergent architecture of visual processing pathways in hierarchically organized structures with increasing complexity in their computations would hint to limited degrees of freedom for the evolution of visual capabilities.

视觉是大多数鸟类和哺乳动物的核心感觉，因此这两个类别的视觉系统都表现出显着的适应和专门化。一个共同点是视觉信息是沿着两条主要路径处理的——丘脑路径和顶盖路径。然而，这些途径之间的分工差异很大，不仅在类之间，而且在每个类的不同物种之间也是如此。一般来说，视觉系统似乎具有高度可变性和适应性，使其成为研究神经处理进化优化的主要目标。在当前的应用中，我们将重点关注鸽子的丘脑视觉系统。由于我们对这种视觉通路功能特性的大部分了解都源于猫头鹰——一种对夜间捕食生活方式具有高级适应能力的视觉专家——我们的目标是研究通才鸽子的丘脑系统。我们提出的系统探索可以将物种特异性的适应与该处理途径的一般特征分开。与哺乳动物相比，关于鸟类丘脑通路中视觉信息处理的可用数据很少。此外，这些研究所使用的方法也各不相同。特别是使用不同的刺激集阻碍了直接比较。在我们的第一个项目中，我们继续对鸽子的顶盖视觉系统进行三维表征。我们的结果表明，所提出的该视觉系统的类皮层解剖结构也体现在信息处理的生理学中。在即将到来的项目中，我们为丘脑视觉系统提出了一种类似的方法。这提供了独特的机会来比较两个视觉系统（使用相同的刺激和方法进行研究）对鸽子视觉处理的贡献。除了视觉系统的功能表征之外，该项目还旨在利用高密度电生理学和光遗传学操作来因果测试丘脑通路内的计算层次结构。我们将检验丘脑视觉系统与哺乳动物皮层共享解剖学和计算特性的假设。在这里，我们对单个单元、局部场势及其振荡的系统记录，以及与哥廷根同事合作的信息论方法，将深入了解不同层次的视觉信息的处理。分层组织结构中的视觉处理路径的聚合架构随着计算复杂性的增加而暗示视觉能力进化的自由度有限。