Neural coding and functional organization of the octopus visual system

摘要 鲸类有着巨大而复杂的大脑，特别是一个功能强大的视觉系统。 然而，它们的大脑独立于脊椎动物进化，人们对神经如何进化知之甚少 头足类动物大脑中的回路处理视觉信息。事实上，从来没有直接的 头足类动物中央视觉系统感受野的记录。这项研究将衡量 章鱼视叶的神经活动和视觉编码，一个新兴的模型 用于头足类研究的生物。第一个目标将采用双光子钙成像在光学 幼章鱼的叶，结合受控的视觉刺激，以测量感受野特性 单个神经元的大集合。第二个目标是将联合收割机这种功能成像与 通过逆行追踪识别的解剖连接，以确定视觉信息如何路由 通过视觉系统进入与特定行为相关的高级大脑区域。第三 aim将把这些实验结果结合到视觉特征的计算分析中， 编码，并转化为视觉处理的网络模型。总之，这些目标将提供直接的洞察力， 这个独特的视觉系统的神经编码和功能组织。 这项工作将是第一个描述头足类动物中央视觉系统的神经计算。 对一个在进化上不同但在功能上与脊椎动物系统平行的系统的研究， 有可能阐明视觉处理的新方法。同样地， 观察头足类动物功能组织的趋同性，相对于脊椎动物和其他 无脊椎动物，如果蝇，将有助于确定功能所需的关键特征， 复杂的视觉系统

ABSTRACT Cephalopods have large and complex brains, and in particular a highly capable visual system. However, their brains evolved independently from vertebrates, and very little is known about how neural circuits in the cephalopod brain process visual information. In fact, there has never been a direct recording of receptive fields in the central visual system of cephalopods. This study will measure neural activity and visual coding in the optic lobe of Octopus bimaculoides, an emerging model organism for cephalopod research. The first aim will employ two-photon calcium imaging in the optic lobe of juvenile octopuses, combined with controlled visual stimuli, to measure receptive field properties in large ensembles of individual neurons. The second aim will combine this functional imaging with anatomical connectivity, identified via retrograde tracing, to determine how visual information is routed through the visual system and into higher brain regions associated with specific behaviors. The third aim will incorporate these experimental results into computational analysis of the visual features being encoded, and into network models of visual processing. Together, these aims will provide direct insight into the neural coding and functional organization of this unique visual system. This work will be the first to describe neural computations in the central visual system of cephalopods. Examination of a system that is evolutionarily distinct, yet functionally parallel to the vertebrate system, has the potential to illuminate novel ways by which visual processing can be carried out. Likewise, observation of convergence of functional organization in cephalopods, relative to vertebrates and other invertebrates, such as Drosophila, would help identify key features necessary for the function of complex visual systems.