Development of coarse-to-fine spatial processing throughout the primary visual system

项目摘要 视觉系统以时间动态的方式编码视觉刺激，其中刺激的某些方面是 在其他人之前处理。这种趋势的一个主要例子是空间频率（SF）调谐的个别神经元中， 初级视皮层（V1）。这些细胞最初被调谐为更喜欢较低SF的粗糙刺激;然而，在整个过程中， 短暂的反应，他们的调谐配置文件转移到更好的，高SF刺激。这种由粗到精的SF处理模式 在小鼠、猫、非人类灵长类动物和人类中发现，这表明它可能是空间的一个基本属性。 视野尽管如此，目前尚不清楚这一过程是否像许多人一样以经验依赖的方式在出生后发展 空间视觉的其他方面。此外，从粗到细SF处理的神经回路和机制 并没有得到很好的理解。 为了开始了解从粗到细的SF处理背后的神经回路的发展，研究者 将在小鼠初级视觉系统的整个发育过程中研究这种时间动态过程。一是 研究者将在整个出生后早期表征V1中由粗到细的SF加工，并测试视觉的作用。 推动这一发展的经验。这将通过使用小鼠的多通道细胞外记录来完成， 发育年龄以及在黑暗中饲养的成年小鼠。第二，从粗到细的SF处理的程度是 通过记录背外侧膝状体核（dLGN）和上级丘来确定皮质来源 (SC)成年老鼠下行皮层反馈的作用也将通过化学沉默皮层来测试， 这些皮层下结构的记录。最后，研究者将评估为什么皮质回路从粗到细发展 通过确定该时间动态过程是否能够实现自然图像的有效编码来进行SF处理。 总的来说，这些结果将提供新的和重要的信息，关于出生后发展的粗到 精细的SF处理贯穿主要视觉通路，并将开始揭示这一过程与编码的关系 复杂的自然图像。此外，所述的研究计划将为申请人提供额外的 需要接受技术、概念、计算和科学方面的培训，成为一名有竞争力的独立科学家。最后 拟议的研究将在一个激励的科学环境中进行，并拥有看到该项目所需的所有资源 完成这一协作科学界强烈支持拟议的研究及其成功。

PROJECT SUMMARY The visual system encodes visual stimuli in a temporally dynamic fashion, where certain aspects of a stimulus are processed before others. A prime example of this trend is the spatial frequency (SF) tuning of individual neurons in the primary visual cortex (V1). These cells are initially tuned to prefer coarse stimuli of lower SF; however, throughout their brief responses their tuning profiles shift to preferring finer, high SF stimuli. This coarse-to-fine pattern of SF processing has been found in mice, cats, non-human primates and humans, suggesting it may be a fundamental property of spatial vision. Despite this, it is unclear whether this process develops postnatally in an experience-dependent fashion, like many other aspects of spatial vision. Furthermore, the neural circuits and mechanisms underlying coarse-to-fine SF processing are not well understood. To begin to understand the development of and neural circuitry behind coarse-to-fine SF processing, the investigator will study this temporally dynamic process throughout development of the mouse primary visual system. First, the investigator will characterize coarse-to-fine SF processing in V1 throughout early postnatal life and test the role of visual experience in driving this development. This will be done by using multichannel extracellular recordings in mice at key developmental ages as well as in dark-reared adult mice. Second, the extent to which coarse-to-fine SF processing is cortically derived will be determined by recording from the dorsal lateral geniculate nucleus (dLGN) and superior colliculus (SC) of adult mice. The role of descending cortical feedback will also be tested by chemically silencing the cortex while recording from these subcortical structures. Finally, the investigator will assess why cortical circuit develop coarse-to-fine SF processing by determining if this temporally dynamic process enables the efficient coding of natural images. Collectively, these results will provide novel and important information regarding the postnatal development of coarse-to- fine SF processing throughout the primary visual pathway and will begin to unveil how this process relates to coding complex natural images. Moreover, the research plan described within will provide the applicant with the additional technical, conceptual, computational and scientific training needed to be a competitive, independent scientist. Finally, the proposed research will take place in a stimulating scientific environment with all the resources required to see this project to completion. This collaborative scientific community is strongly supportive of the proposed research and its success.