How Does Normalization Regulate Visual Competition?

项目摘要/摘要 人类视觉系统如何调节相互竞争的感觉信息？流行的理论认为 一种被称为分裂归一化的计算在管理神经竞争方面发挥着关键作用。正规化 被认为是一种规范的神经计算，潜在地驱动整个大脑的反应。有趣的是， 有证据表明，正常化的普遍作用依赖于对刺激的精细调整 特征，例如方向和空间频率，但归一化的这种特征选择性质是 令人惊讶的是研究不足，特别是在人类身上。我们的长期目标是了解神经机制 支持人类视觉层次结构的视觉，并表征它们如何灵活地随 选择性注意。这项提议的目的是使用最先进的功能神经成像技术 和分析，以阐明允许归一化控制人口的调整特征 了解人类视觉皮质内的反应，并了解正常化如何支持选择性注意。 我们首先通过刻画早期视觉中归一化的选择性属性来解决这个问题 在正常的、被动的、场景观看期间的大脑皮层。然后，我们将基于以下内容评估模型的统一潜力 分裂的正常化，考察正常化在通过空间-竞争调节竞争中所起的作用 定向和基于特征的注意力。通过揭示人类视觉中调谐归一化所起的作用 这些研究将为开发诊断工具和 治疗涉及中央视觉处理缺陷的临床疾病。

PROJECT SUMMARY/ABSTRACT How does the human visual system regulate competing sensory information? Prevailing theories propose that a computation known as divisive normalization plays a key role in governing neural competition. Normalization is considered a canonical neural computation, potentially driving responses throughout the brain. Interestingly, there is evidence to suggest that normalization’s pervasive role relies on an exquisite tuning to stimulus features, such as orientation and spatial frequency, but this feature-selective nature of normalization is surprisingly understudied, particularly in humans. Our long-term goal is to understand the neural mechanisms supporting vision across the visual hierarchy in humans, and to characterize how they flexibly change with selective attention. The aim of this proposal is to employ state-of-the-art functional neuroimaging techniques and analyses to shed light on the tuning characteristics that allow normalization to control population responses within human visual cortex, and to understand how normalization can support selective attention. We approach the problem by first characterizing the selective properties of normalization within early visual cortex during normal, passive, scene viewing. We will then assess the unifying potential of models based on divisive normalization, examining the role that normalization plays in regulating competition via spatially- directed and feature-based attention. By revealing the role played by tuned normalization within human visual cortex, these studies will provide the necessary framework for the development of diagnostic tools and treatments for clinical disorders that involve deficits in central visual processing.