Understanding the neuronal substrates of flexible visual processing in everyday life

“视觉处理主要是在静态条件下研究的，受试者(人类或动物模型)在此条件下不动。虽然在这些条件下视觉处理的基本要素已经确立，但令人惊讶的是，我们对更自然条件下的视觉处理知之甚少，在更自然的条件下，受试者在自然环境中移动。在过去的十年里，对啮齿动物、鱼类、苍蝇和人类的研究提供了强有力的证据，表明运动动作对视觉系统中的神经活动有重大影响，并表明视觉处理在很大程度上受到受试者的行为状态的控制。这一新情景与解剖学数据相一致，解剖学数据表明，视觉丘脑的突触输入只有一小部分来自视网膜，而其余的突触来自皮质和其他丘脑和脑干核团的投射。我们目前对视网膜投射有很好的了解，但我们对所有根据行为状态调节视觉处理的非视网膜投射知之甚少。“我们的研究旨在解决我们在自然、现实生活条件下对视觉处理的理解中的这些主要差距。更具体地说，我们解决了四个问题：1)关于行为状态的信息被传达到视觉丘脑？2)关于行为状态的信息是如何与传入的视觉信息整合的？这种整合对视觉加工有什么影响？3)这些信息的来源是什么？大脑的哪些区域提供哪种类型的信息？4)视觉丘脑中的行为信息如何以及在多大程度上影响后续行为中的动作选择？要做到这一点，我们将利用我们测量自由行为动物的3D运动动作的能力[1]，结合同步的脑记录(与[2]相同，但来自高通量~1000通道神经像素电极[3])和明确定义的细胞类型的光遗传刺激。使用我们内部构建的计算分析平台，向视觉丘脑的解剖投射将进一步结合在小鼠体内注射Brainrow病毒与在整个大脑中进行轴突投射的单细胞重建[4]。学生将接受关于急性和慢性(自由移动)电生理学、活体光遗传学、通过病毒注射和共聚焦显微镜进行电路追踪的培训，以及用于分析行为和神经元活动的计算方法。该项目将是Riccardo Storchi博士(主要监管人)、Timothy Brown教授和Rasmus Petersen实验室以及Nina Milosavljevic博士之间的密切合作

"Visual processing has mostly been studied in static conditions in which subjects (humans or animal models) do not move. While in these conditions the basic elements of visual processing have been established, we know surprisingly little about visual processing in more natural conditions, in which the subjects move around their natural environments. Over the last decade studies in rodents, fishes, flies and humans provided robust evidence indicating that motor actions have major effects on neural activity in the visual system and indicating that visual processing is heavily controlled by the behavioral state of the subject. This new scenario is consistent with anatomical data indicating that only a small fraction of synaptic inputs to visual thalamus comes from the retina, while the rest is constituted by projections from cortex and other thalamic and brainstem nuclei. We currently have a good understanding of the retinal projections, but we know little about all the non-retinal projections that modulate visual processing according to behavioural states."Our research aims to address these major gaps in our understanding of visual processing in natural, real-life conditions. More specifically we address four questions: 1) What informations about behavioural state are conveyed to the visual thalamus?2) How informations about behavioural states are integrated with the incoming visual information? What is the effect of such integration on visual processing? 3) What is the source of these information? Which brain areas provide which type of information? 4) How and to what extent behavioural information in visual thalamus affects action selection in subsequent behaviors? To do that, we will take advantage of our ability to measure 3D motor actions in freely behaving animals [1], combined with simultaneous brain recordings (as in [2] but from high-throughput ~1000 channel Neuropixel electrodes [3]) and optogenetic stimulation of well-defined cell types. The anatomical projections to the visual thalamus will be further characterized by combining injections of Brainbow viruses in mice with single cell reconstruction of axonal projections in whole brains [4] using our in house-built computational analysis platform.The student will be trained in acute and chronic (freely moving) electrophysiology, in vivo optogenetics, circuit tracing through viral injections and confocal microscopy, computational methods for analyzing behavior and neuronal activity. The project will be a close collaboration between Dr Riccardo Storchi lab (main supervisor), Profs Timothy Brown and Rasmus Petersen labs and Dr Nina Milosavljevic