Mechanisms of Bottom-up and Top-down Control of Spatial Attention

描述(由申请人提供)：竞争性刺激选择如何在细胞和电路水平上发挥作用？在灵长类动物中，刺激选择以两种根本不同的方式控制：自下而上和自上而下。我们已经开发了自动化的行为任务，在鸡身上展示了对刺激选择的两种控制。在灵长类动物中，中脑网络对于竞争性选择至关重要。导致一个刺激的选择和所有其他刺激的抑制的回路是什么，它们是如何工作的？中脑网络在从鱼类到哺乳动物的脊椎动物中高度保守，在鸟类中分化最大。高度分化的鸟类网络提供了测试失活特定的、专门的回路对刺激选择行为的影响的机会。对鸟类的初步研究表明，特定的胆碱能回路有助于自下而上地控制刺激选择，而特定的GABA能回路参与竞争刺激的抑制。在目标1和目标2中，我们定量地分析了鸡竞争刺激选择的自下而上和自上而下控制的性质。在目标3中，我们测试了专门的胆碱能和GABA能回路对自下而上和自上而下控制刺激选择的各自贡献。了解这些回路在选择行为中的作用将极大地促进我们对中脑网络如何执行这些基本功能的理解。这些结果将为未来的记录、失活、微刺激和光遗传学研究注意力控制机制、如何识别特定注意力相关回路的功能障碍以及如何恢复受损网络的功能奠定基础。

DESCRIPTION (provided by applicant): How does competitive stimulus selection work, at the level of cells and circuits? In primates, stimulus selection is controlled in two fundamentally different ways: bottom-up and top- down. We have developed automated behavioral tasks that demonstrate both kinds of control of stimulus selection in chickens. In primates, a midbrain network is essential to competitive selection. What are the circuits that cause the selection of one stimulus and the suppression of all others, and how do they work? The midbrain network is highly conserved across vertebrate species, from fish to mammals, and it is most differentiated in birds. The highly differentiated avian network provides the opportunity to test the effects of inactivating specific, specialized circuits on stimulus selection behavior. Preliminary studies in birds indicate that a specific cholinergic circuit contributes to the bottom-up control of stimulus selection, and that a specific GABAergic circuit participates in the suppression of competing stimuli. In Aims #1 and 2 we analyze quantitatively the properties of bottom-up and top-down control of competitive stimulus selection in chickens. In Aim #3, we test the respective contributions of the specialized cholinergic and GABAergic circuits to bottom-up and top-down control of stimulus selection. Understanding the role of these circuits in selection behavior will greatly advance our understanding of how the midbrain network performs these essential functions. The results will lay the foundation for future recording, inactivation, microstimulation, and optogenetic studies into mechanisms of attention control, how to identify dysfunction of specific attention-related circuits, and how to restore function to damaged networks.