How does the Drosophila brain compute and see visual motion?

果蝇大脑如何计算和观察视觉运动？

• 批准号: BB/F012071/1
• 负责人: Mikko Ilmari Juusola
• 金额: $ 69.45万
• 依托单位: University of Sheffield
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2008
• 资助国家: 英国
• 起止时间: 2008 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=BB%2FF012071%2F1
• 关键词: How; does; Drosophila; brain; compute

Animals have neural mechanisms for detecting visual motion, enabling them to infer the speed and direction of objects that move in visual scenes. With its perceptual advantages the ability to detect motion has shaped the organisation and function of visual systems. However, the way in which the visual systems process and route motion information has proven to be a difficult problem to decipher. This proposal aims to elucidate the functional organisation of neural networks responsible for encoding visual motion in the brain of the fruit fly, Drosophila. We have recently developed an extremely versatile Drosophila preparation that enables us to visualise in real time how a specialised web of motion sensitive neurones (LPTCs) in the brains of transgenic flies translate moving images in the scene into neural activity patterns (calcium and voltage signals). These flies have genetically engineered eyes that are sensitive to ultraviolet (UV) light and brains that express green-sensitive fluorescence proteins (optical reporters) that react to changes in the neural activity (here calcium changes) in LPTCs. Since the spectral sensitivities of the eye and optical reporters do not overlap, we can visualise neural activity in the LPTCs when such a fly looks at moving objects, being oblivious of us simultaneously scanning its brain. In order to fully utilise this novel preparation requires the generation of a unique hybrid experimental apparatus that can visualise calcium signals and measure voltage responses with sharp microelectrodes simultaneously. For live imaging the flies will be placed in this apparatus in which they are presented with moving UV-light patterns while calcium and voltage signals are monitored from the LPTCs. Using this system, together with further genetic modifications in the eyes and the brain of the flies, we wish to investigate how visual motion signals are routed and processed by the fly's visual system. Here we plan to find answers to two important open questions. What is the contribution of different photoreceptor types in routing visual information to the brain so that the speed and direction of objects moving in the scene can be inferred? and what is the contribution of attentional signals from the brain in the visual motion processing? These questions will be studied by monitoring changes in calcium and voltage signals of LPTCs in transgenic flies in which selective neural pathways from the eyes or from the brain can be turned on and off, using temperature-sensitive genetic switches. Furthermore, the visual behaviour of the same flies will be characterised in a flight simulator system running in our laboratory. In this way we shall be able to correlate the genetically targeted changes in the routing and processing of visual motion information to the animal behaviour and cognitive phenomena. In a parallel approach, the results from these experiments will be analysed and modelled mathematically to find answers to the open question of how moving visual objects in the scene are encoded into moving neural images, as represented by activity patterns of networks of interconnected neurones in the brain.

动物具有检测视觉运动的神经机制，使它们能够推断出视觉场景中移动物体的速度和方向。由于其感知优势，检测运动的能力塑造了视觉系统的组织和功能。然而，视觉系统处理和路由运动信息的方式已被证明是一个难以破译的问题。本研究旨在阐明果蝇大脑中负责编码视觉运动的神经网络的功能组织。我们最近开发了一种非常通用的果蝇制剂，使我们能够实时可视化转基因果蝇大脑中运动敏感神经元（lptc）的专门网络如何将场景中的运动图像转化为神经活动模式（钙和电压信号）。这些果蝇具有对紫外线（UV）敏感的基因工程眼睛和表达对LPTCs神经活动变化（这里是钙变化）做出反应的绿色敏感荧光蛋白（光学报告）的大脑。由于眼睛的光谱灵敏度和光学报告器并不重叠，当这种苍蝇看着移动的物体时，我们可以看到LPTCs的神经活动，同时扫描它的大脑，而我们却没有注意到。为了充分利用这种新颖的制备方法，需要产生一种独特的混合实验装置，可以同时显示钙信号和测量尖锐微电极的电压响应。为了进行实时成像，果蝇将被放置在这个装置中，在这个装置中，它们被呈现在移动的紫外线模式下，同时从LPTCs监测钙和电压信号。利用这个系统，再加上对果蝇眼睛和大脑的进一步基因改造，我们希望研究视觉运动信号是如何被果蝇的视觉系统传递和处理的。在这里，我们计划找到两个重要的开放性问题的答案。不同类型的光感受器在将视觉信息传递给大脑，从而推断出场景中移动物体的速度和方向方面有什么贡献？在视觉运动的处理过程中，来自大脑的注意信号有什么贡献？这些问题将通过监测转基因果蝇LPTCs的钙和电压信号的变化来研究，在转基因果蝇中，来自眼睛或大脑的选择性神经通路可以通过温度敏感的基因开关打开和关闭。此外，同样的苍蝇的视觉行为将在我们实验室运行的飞行模拟器系统中进行表征。通过这种方式，我们将能够将视觉运动信息的路径和处理中的遗传目标变化与动物行为和认知现象联系起来。在一个并行的方法中，这些实验的结果将被分析和数学建模，以找到一个悬而未决的问题的答案，即场景中移动的视觉物体是如何被编码成移动的神经图像的，这是由大脑中相互连接的神经元网络的活动模式所代表的。

项目成果

How a fly photoreceptor samples light information in time.

• DOI: 10.1113/jp273645
• 发表时间: 2017-08-15
• 期刊: The Journal of physiology
• 作者: Juusola M;Song Z
• 通讯作者: Song Z

Microsaccadic sampling of moving image information provides Drosophila hyperacute vision.

• DOI: 10.7554/elife.26117
• 发表时间: 2017-09-05
• 期刊: eLife
• 影响因子: 7.7
• 作者: Juusola M;Dau A;Song Z;Solanki N;Rien D;Jaciuch D;Dongre SA;Blanchard F;de Polavieja GG;Hardie RC;Takalo J
• 通讯作者: Takalo J

Microsaccadic sampling of moving image information provides Drosophila hyperacute vision

运动图像信息的微扫视采样提供果蝇超敏锐视觉

• DOI: 10.1101/083691
• 发表时间: 2016
• 作者: Juusola M

Overexpressing temperature-sensitive dynamin decelerates phototransduction and bundles microtubules in Drosophila photoreceptors.

• DOI: 10.1523/jneurosci.2873-09.2009
• 发表时间: 2009-11-11
• 期刊: The Journal of neuroscience : the official journal of the Society for Neuroscience
• 作者: Gonzalez-Bellido PT;Wardill TJ;Kostyleva R;Meinertzhagen IA;Juusola M
• 通讯作者: Juusola M

Neural Information Processing

神经信息处理

• DOI: 10.1007/978-3-319-12643-2_68
• 发表时间: 2014
• 作者: Adams S