Role of top-down feedback in visual perception

项目摘要 视觉信息沿着前馈连接从初级视觉皮层（V1）通过层级结构传播 大脑皮层区域。反过来，视觉皮层接收来自更高层次的反馈（FB）连接的密集网络。 排序皮层区域。FB连接已经被牵连在几种形式的自上而下的影响，如 注意，期望和上下文相关的视觉处理，但FB连接的具体贡献 一直是个谜该提案的目标是揭示FB如何从第二个 视觉皮层区（V2）到初级视觉皮层（V1）影响视觉感知和神经反应特性， 灵长类的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 清醒行为的绒猴执行视觉任务的连接。候选人以前的研究 麻醉的绒猴已经表明，V2 FB影响感受野（RF）的大小，环绕抑制和 V1神经元的反应增益。为了测试这些神经水平的影响如何在感知中表现出来，FB连接 在执行视觉任务的清醒的绒猴中，从V2到V1的投射将被光遗传学失活。 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，但提供了重要的新的训练，在使用清醒的行为绒猴。基因组研究进展 编辑工具和在绒猴中转基因种系传递的成功已经将绒猴定位为 一个重要的神经科学模型系统因此，对清醒行为绒猴的新训练研究将 为过渡到独立提供坚实的基础，并提供一套技能，将定位候选人 在神经科学中使用基因工程绒猴的竞争中领先。

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, and a skill set that will position the candidate ahead of the competition in the use of genetically engineered marmosets in neuroscience.