Plasticity of feedback inputs from Higher Order Visual Areas into Primary Visual Cortex

项目摘要 感官体验的处理，这是导航和与世界互动所必需的，依赖于 很大程度上依赖于来自更高阶皮质区域的反馈输入。这在视觉系统中得到了进一步的强调 其中，高级视觉区域和初级视觉皮质(V1)之间的连接提供了上下文 我们所看到的信息，并允许我们注意到视觉刺激的重要方面。这很好 记录了V1因视觉体验的改变而发生的塑料变化。例如，在 对视觉剥夺的反应，V1通过改变特定层中连接的强度来适应 举止。更具体地说，我们的实验室已经表明，在视觉剥夺后，第2/3层中的侧向连接 强度增加而不改变来自第4层的前馈连接。这些变化很容易 在成年小鼠身上观察到的，这表明视觉剥夺是产生可塑性的一种有效手段 成人的大脑。来自高级视觉区域的反馈投射构成V1的主要侧向输入之一 2/3层神经元。视觉剥夺诱导的可塑性在V1中得到了广泛的研究，但是否和 目前尚不清楚高级视觉区域如何适应视觉体验的变化。我建议把这个填满 通过首先调查来自高阶视觉的密集反馈投影的强度来确定知识差距 视觉剥夺后进入V1层2/3的面积增加(Aim1)。此外，抑制电路也很重要。 调节神经元的反应，并提供另一种控制可塑性的方法。我会调查 V1层2/3的高视觉区域和抑制细胞之间的联系以及如何决定Vison的损失 更改这些连接的强度(AIM2)。最后，我将调查这些反馈的丢失 投射影响V1层2/3神经元的自发活动(目标3)。从这个过程中得到的结果 这项工作将阐明从高级视觉区域到V1的输入如何适应视力丧失，以及如何 这些输入有助于V1的自发活动。此外，因为我提议的研究将在 对于成年人来说，这些结果将提供对成人视觉系统固有可塑性的机械理解，以及 为我们提供了潜在的靶点，以促进V1可塑性，以弥补视觉功能的损失。

Project Summary Processing of sensory experience, which is essential for navigating and interacting with the world, relies heavily on feedback inputs from higher-order cortical areas. This is further emphasized in the visual system where the connectivity between higher-order visual areas and the primary visual cortex (V1) provides context to the information we see, and allows us to pay attention to important aspects of the visual stimuli. It is well documented that V1 undergoes plastic changes in response to altered visual experience. For instance, in response to visual deprivation, V1 adapts by changing the strength of its connections in a layer specific manner. More specifically, our lab has shown that after visual deprivation, lateral connections in layer 2/3 increase in strength without changes in feedforward connections from layer 4. These changes were readily observed in adult mice, which suggests that visual deprivation is an effective means to produce plasticity in the adult brain. Feedback projections from higher-order visual areas constitute one of the major lateral inputs to V1 layer 2/3 neurons. Visual deprivation-induced plasticity has been studied extensively in V1, but whether and how higher-order visual areas adapt to changes in visual experience is currently unknown. I propose to fill this knowledge gap by first investigating if the strength of the dense feedback projections from higher-order visual areas into V1 layer 2/3 is increased after visual deprivation (Aim1). Additionally, inhibitory circuitry is important in modulating responses of neurons and provides another way of controlling plasticity. I will investigate the connections between higher-visual areas and inhibitory cells in V1 layer 2/3 and determine how vison loss changes the strength of these connections (Aim2). Lastly, I will investigate how loss of these feedback projections affects the spontaneous activity of neurons in V1 layer 2/3 (Aim 3). The results obtained from this work will shed light on how inputs from higher-order visual areas to V1 adapt to the loss of vision, and how these inputs contribute to spontaneous activity in V1. Furthermore, because my proposed study will be done in adults, the results will provide mechanistic understanding on the innate plasticity in the adult visual system, and provide us with potential targets to promote V1 plasticity that could compensate for loss of visual function.