Looking with gills: The evolution and function of distributed visual systems in fan worms with a view to future resilient sensor arrays

我们常常着迷于思考其他动物是如何看待世界的。由于大多数生物都有两只主要的眼睛突出地位于头部，我们通常能够想象出对我们自己的观点的某种派生或阐述。然而，在某些情况下，视觉系统与我们的视觉系统背道而驰，以至于很难想象这样的系统如何运作，更不用说为动物提供关于世界的有用信息了。海洋扇虫可以说拥有自然界最奇怪的视觉系统。这些蠕虫在海底的管子里生活，并将它们的同名扇子投射到水柱中，这些扇子由许多被称为电离线的触须组成。这些电离层负责过滤进食、呼吸和令人惊讶的视力。在许多物种中，漏斗上覆盖着各种排列的眼睛；有时散布在所有漏斗上，有时在两个漏斗的尖端聚集成一对大的复眼，几乎以任何排列之间的排列。这些眼睛很可能起到了光学防盗报警器的作用，探测到迫在眉睫的威胁的移动，并刺激快速撤退到防御工事的管子里。我的研究表明，这些放射光的眼睛代表了一种全新的进化发展，使用了不同于任何其他动物眼睛的感光基因和神经通路。这些特征使得扇形蠕虫成为一个壮观的研究系统，用于探索视觉的起源以及分布式视觉感觉系统中复杂性和组织的发展。我建议使用分子、神经生物学和计算方法来研究扇形蠕虫的放射状眼睛的进化和功能。下一代测序技术将被用于识别与光检测和光转导有关的基因，以及导致在不同种类的扇形蠕虫中观察到的眼睛不同排列的发育线索。我还将追踪从眼睛到大脑的神经元投射，以了解来自看似混乱的分布的眼睛或眼球细胞阵列的信息是如何整合和解释的，以便刺激可靠的惊吓反应。最终，我将利用这些研究，为简单、冗余、分布式的光学传感器阵列产生一个合成模型，这将对仿生机器人学产生影响。

We are often fascinated to ponder how other animals see the world. Since most creatures have two primary eyes positioned prominently on the head, we are generally able to imagine some derivation or elaboration of our own view. However, there are some cases in which the visual system departs so wildly from ours that it is difficult to conceive how such a system would function, let alone provide the animal with useful information about the world. Marine fan worms possess arguably the most bizarre visual system in nature. These worms spend their lives within tubes on the sea floor, and project their eponymous fans, composed of numerous tentacles called radioles, up into the water column. These radioles are responsible for filter feeding, respiration, and amazingly - vision. In many species, the radioles are covered with variable arrangements of eyes; sometimes scattered in the hundreds on all of the radioles, other times consolidated into a pair of large compound eyes on the tips of two radioles, and in almost any arrangement in-between. These eyes likely function as a sort of optical burglar alarm, detecting the movement of looming threats and stimulating a rapid withdrawal into the fortified tube. My research has suggested that these radiolar eyes represent a completely novel evolutionary development, using light-sensing genes and neural pathways unlike those in the eyes of any other animal. These features make fan worms a spectacular study system to explore the origins of vision and the development of complexity and organization in distributed visual sensory systems. I propose to investigate the evolution and function of radiolar eyes in fan worms using molecular, neurobiological, and computational approaches. Next-generation sequencing techniques will be used to identify the genes involved in light detection and phototransduction, as well as developmental cues that give rise to the variable arrangements of eyes observed in different species of fan worms. I will also trace neuronal projections from the eyes to the brain in order to understand how information from a seemingly-chaotic, distributed array of eyes or ocelli is integrated and interpreted in order to stimulate a reliable startle response. Ultimately, I will draw upon these investigations in order to produce a synthetic model for simple, redundant, distributed optical sensory arrays that will have implications to biomimetic robotics.