The Computation of Direction Selectivity in the Retina

运动的视觉检测是通过神经元来实现的，神经元有选择地对视野中的运动方向做出反应。当移动的物体以适当的方向穿过视网膜神经节的感受野时，视网膜神经节中的细胞会发出开/关反应。这意味着存在抑制这些细胞反应的神经回路，而这些回路正是这个项目的研究对象。该研究解决了四个主要问题：1。这些细胞对方向选择是必不可少的，还是仅仅决定速度和方向？2. 抑制是如何与视网膜中的兴奋相互作用的？3. 这种抑制与细胞对速度和方向选择性的调整有什么关系？4. 抑制在多大程度上依赖于被感知物体运动的对比？采用电生理学、药理学和免疫组织化学等方法，并对数据进行计算理论分析。这项工作意义重大，原因有很多。它包括对可能是大脑功能基础的一般机制的分析。它还将展示早期运动测量的局限性，可能会对运动感知的期望设置限制。最后，它包括新的实验和理论工具的发展，将适用于研究运动感知机制在大脑的高级中心。*** //

Visual detection of motion occurs via neurons that selectively respond to the direction of movement in the visual field. Cells in the retinal ganglia give ON/OFF responses when moving objects cross their receptive fields in appropriate directions. This implies that there are neural circuits that inhibit the responses of these cells, and it is those circuits that are the object of investigation in this project. The study addresses four major questions: 1. Are these cells essential to direction selectivity or do they simply function in determining velocity and orientation? 2. How does the inhibition interact with excitation in the retina? 3. How does the inhibition relate to the cells' tuning to velocity and direction selectivity? 4. How dependent is the inhibition on the contrast of the object whose motion is being perceived? The methods employed include electrophysiology, pharmacology and immunohistochemistry, with computational theoretical analysis of the data. The work is significant for a number of reasons. It includes analysis of general mechanisms that are probably fundamental to the function of the brain. It will also demonstrate the limitations of early motion measurements, perhaps setting constraints on what may be expected of motion perception. Finally, it includes the development of new experimental as well as theoretical tools that will be applicable to studies of motion perception mechanisms in higher centers of the brain. *** //