Eyes over ears? Bats as neuroethological models for understanding visual capture

眼睛盖过耳朵？

• 批准号: RGPIN-2014-04872
• 负责人: Ratcliffe, John
• 金额: $ 3.64万
• 依托单位: University of Toronto
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2018
• 资助国家: 加拿大
• 起止时间: 2018-01-01 至 2019-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=663030
• 关键词: Eyes; over; ears; Bats; neuroethological

How we perceive the world depends on the environmental information available to our senses and our brain's ability to integrate the resulting neural information into a unified experience. My long-term objective is better understand how animals - vertebrates and invertebrates alike - use sensory information to construct internal representations of their often changing external environments. Over the course of this 5-year research grant, I will use bats to investigate how they and other vertebrates, including ourselves, combine visual and auditory information to build representations of the spatial arrangements of objects in our surroundings. Such representations are important for orientation and object recognition and are used to make decisions about what to eat, what to avoid, who to court, and how to get home. Among the senses, vision and hearing have most in common and the greatest potential for similarity in the way the brain represents the information gathered through them. For this same reason, if visual and auditory information are contradictory there is potential for confusion, especially if the brain cannot quickly decide which is the more accurate and reliable source.* For many birds and mammals, when auditory and visual information do not agree, the brain often chooses visual over auditory information to localize objects. Several explanations, none mutually exclusive, have been suggested to account for this. One is historical - because vision precedes hearing in the evolution of vertebrates, vision has had a greater impact on the evolution of hearing than hearing has had on vision. A second is developmental - suggesting that as the brain develops the visual system has a disproportionate influence on how the auditory system builds images of the outside world. A third postulates that the brain makes real-time estimations on the relative value of available visual and auditory information. This last explanation implies that visual dominance largely results because for much of the time for many animals visible light is more reliable than audible sound. Testing these different hypotheses using bats as subjects is the focus of my research proposal.* Bats have evolved to operate under the cover of night. The majority of today's species, through extraordinary adaptations to their auditory and vocal systems, are able to `see' with their ears. As a result of laryngeal echolocation, bats can do things that non-echolocating animals cannot do using sound: based on the echoes from their calls they can accurately determine an object's distance and also its size, shape, and texture. Bats are not blind, but because many species rely more on echoes than light for orientation, bats provide an excellent opportunity to study how the mammalian brain builds visual and auditory images and how evolution, development, and current environmental conditions each impact how mammals, faced with conflicting information, decide which sense to rely on.* Evolution, development, and current conditions must all exert an influence on how vertebrates prioritize and integrate audio-visual information. I will conduct behavioural, comparative, and neuroanatomical studies to disentangle their roles. I have also designed experiments to see if some bats are capable of cross-modal recognition. That is do bats perceive through echolocation images similar to those perceived through vision? In meeting these short-term objectives, my research will add to our understanding of how animals build coherent internal representations of the world around them. Ultimately, the results may help us to better comprehend aspects of the autism spectrum and schizophrenia, disorders associated with difficulties in integrating sensory information.

我们如何感知世界取决于我们感官所能获得的环境信息，以及我们大脑将由此产生的神经信息整合成统一体验的能力。我的长期目标是更好地了解动物-脊椎动物和无脊椎动物-如何使用感官信息来构建其经常变化的外部环境的内部表征。在这个为期5年的研究基金的过程中，我将使用蝙蝠来研究它们和其他脊椎动物，包括我们自己，如何将联合收割机视觉和听觉信息结合起来，以建立我们周围物体的空间排列的表征。这种表征对于定向和物体识别很重要，并用于决定吃什么、避免什么、向谁求助以及如何回家。在感官中，视觉和听觉在大脑表示通过它们收集的信息的方式上具有最大的共同点和最大的相似性。基于同样的原因，如果视觉和听觉信息相互矛盾，就有可能产生混淆，特别是当大脑无法迅速决定哪一个信息来源更准确、更可靠时。 对于许多鸟类和哺乳动物来说，当听觉和视觉信息不一致时，大脑通常会选择视觉信息而不是听觉信息来定位物体。有人提出了几种解释来解释这一点，但这些解释并不相互排斥。一个是历史的，因为在脊椎动物的进化中，视觉先于听觉，视觉对听觉进化的影响比听觉对视觉的影响更大。第二个是发展性的--这表明随着大脑的发展，视觉系统对听觉系统如何构建外部世界的图像有着不成比例的影响。第三种假设是大脑对可用的视觉和听觉信息的相对价值进行实时估计。最后一种解释意味着视觉优势的产生主要是因为在大多数时间里，对许多动物来说，可见光比可听声更可靠。以蝙蝠为研究对象来检验这些不同的假设是我研究计划的重点。 蝙蝠已经进化到可以在夜晚的掩护下活动。今天的大多数物种，通过对听觉和发声系统的非凡适应，能够用耳朵“看”。由于喉部回声定位，蝙蝠可以做一些非回声定位动物无法使用声音做的事情：根据它们叫声的回声，它们可以准确地确定物体的距离，以及它的大小，形状和质地。蝙蝠并不是盲人，但由于许多物种更多地依靠回声而不是光来定位，蝙蝠提供了一个很好的机会来研究哺乳动物大脑如何构建视觉和听觉图像，以及进化、发育和当前环境条件如何影响哺乳动物，面对相互矛盾的信息，决定依靠哪种感觉。 进化、发展和当前的条件都必须对脊椎动物如何优先考虑和整合视听信息产生影响。我将进行行为，比较和神经解剖学研究，以解开他们的角色。我还设计了一些实验，看看一些蝙蝠是否有跨模态识别的能力。那就是蝙蝠通过回声定位图像的感知与通过视觉感知的相似吗？在实现这些短期目标的过程中，我的研究将增加我们对动物如何建立对周围世界的连贯内部表征的理解。最终，这些结果可能有助于我们更好地理解自闭症谱系和精神分裂症的各个方面，这些疾病与整合感觉信息的困难有关。