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

项目总结 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 先于其他人处理的。这种趋势的一个最好的例子是大脑中单个神经元的空间频率(SF)调谐 初级视皮层(V1)。这些细胞最初被调整为更喜欢较低SF的粗略刺激；然而，在整个过程中 简短的反应他们的调谐曲线转向更精细、更高的SF刺激。这种从粗略到精细的SF处理模式 已经在老鼠、猫、非人类灵长类动物和人类身上发现，这表明它可能是空间的一种基本特性 幻象。尽管如此，尚不清楚这一过程是否会像许多人一样，在出生后以一种依赖经验的方式发展 空间视觉的其他方面。此外，从粗到精的SF加工背后的神经电路和机制 都没有被很好地理解。 为了开始了解从粗略到精细的SF加工背后的神经回路的发展，研究人员 将在小鼠初级视觉系统的整个发育过程中研究这一时间动态过程。首先， 研究人员将表征出生后早期V1中从粗到细的SF加工过程，并测试视觉的作用 推动这一发展的经验。这将通过使用多通道细胞外记录在KEY的小鼠来完成 发育年龄以及黑暗饲养的成年小鼠。第二，从粗略到精细的SF处理的程度 皮质来源将通过记录背侧膝状核(DLGN)和上丘来确定 (SC)成年小鼠。下行皮质反馈的作用也将通过化学方法沉默皮质来测试。 从这些皮质下结构进行记录。最后，研究人员将评估大脑皮层环路由粗变细的原因。 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。 总而言之，这些结果将提供关于从粗到粗的出生后发育的新的重要信息。 在整个主要视觉通路中进行精细的SF处理，并将开始揭示此过程与编码的关系 复杂的自然图像。此外，上述研究计划将为申请人提供额外的 技术、概念、计算和科学培训需要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刺激的科学环境中进行，并拥有观看该项目所需的所有资源 为了完成。这一合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.