Excitation and Inhibition in Neural Circuits of the Visual Cortex

描述(由申请人提供)：初级视觉皮质的神经回路对于产生对外部世界的准确感知至关重要。这些回路在功能上跨越视皮层的垂直轴和水平轴。尽管如此，垂直和水平投影对视觉计算的显著贡献却鲜为人知。特别是，兴奋和抑制的平衡(E/I平衡)是垂直的 由于缺乏适当的方法，在感觉诱发活动中产生的水平投射没有得到很好的描述。这项提议的第一个目标是实施一种新的方法，使用细胞类型特定基因打靶和光遗传工具的组合来选择性地激活皮质每一层的垂直和水平投射。第二个目标是使用这种新的方法来测试这样一个假设，即垂直和水平投影在皮质中产生特定于层的E/I平衡，这决定了它们对皮质活动的功能影响。第三个目标是确定视觉皮层环路中垂直和水平投影产生的不同的E/I平衡如何调节基本刺激特征的编码，如对比度和大小。

DESCRIPTION (provided by applicant): Neural circuits of the primary visual cortex are critical for generating accurate perceptions of our external world. These circuits are functionally organized across both the vertical and horizontal axes of the visual cortex. Nonetheless, the distinct contributions of vertical and horizontal projections to visual computation are poorly understood. In particular, the balance of excitation and inhibition (the E/I balance) that vertical and horizontal projections generate during sensory evoked activity is not well characterized due to a lack of appropriate methodology. The first goal of this proposal is to implement a new approach to selectively activate the vertical and horizontal projections for each layer of the cortex using a combination of cell-type specific gene targeting and optogenetic tools. The second goal is to use this new approach to test the hypothesis that vertical and horizontal projections generate layer-specific E/I balances in the cortex that determine their functional impact on cortical activity. The third goal is to establish how the distinct E/I balances that vertcal and horizontal projections generate in visual cortical circuits mediate the encoding of fundamental stimulus features such as contrast and size.