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，使它们能够推断出在视觉场景中移动的物体的速度和方向。凭借其感知优势，检测运动的能力已塑造了视觉系统的组织和功能。但是，事实证明，视觉系统过程和路线运动信息的方式是一个很难解密的问题。该建议旨在阐明负责编码果蝇大脑中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苍蝇的大脑中专门的运动敏感神经元（LPTC）如何将现场移动图像转化为神经活动模式（钙和电压信号）。这些苍蝇具有对紫外线（UV）光和大脑敏感的基因设计的眼睛，这些光和大脑表达绿色敏感的荧光蛋白（光学记者）对LPTC中神经活动的变化（此处的钙变化）反应。由于眼睛和光学记者的光谱敏感性不会重叠，因此，当这种苍蝇看着移动物体，忽略我们同时扫描大脑时，我们可以看到LPTC中的神经活动。为了充分利用这种新颖的制备，需要产生独特的混合实验设备，该设备可以可视化钙信号并同时使用锋利的微电极来测量电压响应。对于实时成像，将果蝇放置在该设备中，其中将它们带有移动的紫外线模式，同时从LPTC监测钙和电压信号。使用该系统，以及在眼睛和苍蝇的大脑中进行进一步的遗传修饰，我们希望研究如何通过Fly的视觉系统将视觉运动信号路由和处理。在这里，我们计划找到两个重要的开放问题的答案。不同的光感受器类型在将视觉信息路由到大脑中的贡献是什么，以便可以推断在场景中移动的物体的速度和方向？在视觉运动处理中，大脑注意信号的贡献是什么？这些问题将通过监测转基因苍蝇中LPTC的钙和电压信号的变化来研究，其中使用温度敏感的遗传开关可以从眼睛或大脑的选择性神经通路打开和关闭。此外，在我们的实验室运行的飞行模拟器系统中，相同苍蝇的视觉行为将被表征。通过这种方式，我们将能够将视觉运动信息的路由和处理的遗传靶向变化与动物行为和认知现象相关联。在类似的方法中，将对这些实验的结果进行数学分析和建模，以找到对场景中移动视觉对象如何编码为移动神经图像的开放问题的答案，如大脑中互连神经元网络的活动模式所示。

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

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

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

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

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