Role of top-down feedback in visual perception

项目总结 视觉信息沿着前馈连接从初级视觉皮质(V1)通过层次结构传播 大脑皮层区域。反过来，视觉皮质从高层接收一个密集的反馈网络(FB)连接 对皮质区进行排序。FB关系与几种形式的自上而下的影响有关，例如 注意力、期望和上下文相关的视觉加工，但FB连接的具体贡献 对视觉感知的影响一直是个谜。这项提议的目标是揭示FB是如何从第二个 视皮质面积(V2)到初级视皮层(V1)影响视知觉和神经反应特性 灵长类动物的V1神经元。这一目标将通过靶向FB轴突的光遗传失活来实现 在清醒状态下表现为执行视觉任务的绒猴的连接。考生以前在中国学习的情况 麻醉的绒猴已经表明，V2FB影响感受野(RF)的大小、周围抑制和 V1神经元的反应增益。为了测试这些神经水平的影响是如何在感知中表现出来的，FB连接 在清醒的猕猴执行视觉任务时，从V2到V1的投射将被光基因灭活。 拟议的项目直接建立在候选人现有的光遗传学、电生理学和 心理物理学，但在使用清醒行为的绒猴方面提供了重要的新培训。基因组研究进展 编辑工具和转基因生殖系在绒猴中传播的成功将绒猴定位为 神经科学的一个重要模型系统。因此，新的觉醒行为绒猴研究培训将 为过渡到独立提供坚实的基础，这一技能集将使候选人领先于 在神经科学中使用基因工程绒猴的竞争。这样做的目的是 行政补充是为了抵消至少部分对本项目和 获奖者的职业生涯被新冠肺炎。

PROJECT SUMMARY Visual information travels along feedforward connections from the primary visual cortex (V1) through a hierarchy of cortical areas. In turn, the visual cortex receives a dense network of feedback (FB) connections from higher order cortical areas. FB connections have been implicated in several forms of top-down influences, such as attention, expectation, and context dependent visual processing, but the specific contributions of FB connections to visual perception have remained mysterious. The goal of this proposal is to uncover how FB from the second visual cortical area (V2) to primary visual cortex (V1) affects visual perception and neural response properties of V1 neurons in primates. This goal will be achieved by targeting optogenetic inactivation to the axons of FB connections in awake behaving marmosets performing visual tasks. Candidate’s previous studies in anesthetized marmosets have shown that V2 FB affects receptive field (RF) size, surround suppression and response gain of V1 neurons. To test how these neural level effects manifest in perception, FB connections projecting from V2 to V1 will be optogenetically inactivated in awake marmoset monkeys performing visual tasks. The proposed project builds directly upon the candidate’s existing training in optogenetics, electrophysiology and psychophysics, but provides significant new training in using awake behaving marmosets. Advances in genome editing tools and success in transgene germline transmission in marmosets have positioned the marmoset as an important model system for neuroscience. Therefore, new training in awake behaving marmoset research will provide a strong foundation for transitioning to independence, a skill set that will position the candidate ahead of the competition in the use of genetically engineered marmosets in neuroscience. The purpose of this administrative supplement is to offset at least some of the negative effects caused to this project and the awardee’s career by COVID-19.