Where orientation selectivity arises, and how it can change

描述（由申请人提供）：取向选择性背后的机制是什么？虽然方向感知是视觉科学中研究最广泛的元素之一，但我们对视觉系统的这一基本特征仍知之甚少。本研究将心理物理学与认知神经科学的新兴技术结合起来，探讨三个主要问题：（1）方向选择性的来源是什么？虽然方向处理仍然是视觉系统中研究最广泛的特征之一，但关于这种选择性的基本机制仍然存在相当大的争议。在第一个实验中，我将使用经颅磁刺激（TMS），一种暂时抑制皮层活动区域的非侵入性工具，以界定人类方向选择性的来源。(2)意识状态能调节定向选择性吗？在第二个实验中，我建议探索方向调节的灵活性，询问观察者看到刺激的能力是否取决于我们对该刺激的选择性。我将使用双眼竞争来操纵刺激的可见性，同时心理测量方向选择性的带宽。这些结果不仅揭示了方向调整的机制，但也将揭示一个迄今为止尚未探索的方面的双眼竞争：竞争的知觉状态的选择性的作用。(3)方向之间的相互作用是什么？在第三个实验中，我将研究一个已建立的知觉错觉的来源：倾斜排斥效应。有人认为，这种错觉，它产生于不同的方向表征之间的相互作用，有皮质内的起源。我将使用经颅磁刺激，结合心理物理学，帮助隔离这种相互作用的来源。在完成我的培训后，我计划追求一个大学教授职位，研究视觉感知，目标是将生理发现与人类行为联系起来。为此，拟议研究的广泛目标是通过创新的新理论和经验方法获得专业知识，例如方向选择性和TMS模型，使我能够更好地建立这种联系。除了提高我们对人类视觉系统的理解外，拟议的研究还将为公共卫生提供重大利益。研究双眼竞争与我们对弱视等视觉障碍的理解直接相关，弱视是指不同的信号进入双眼。此外，使用TMS的拟议研究将加强我们对一项新兴技术的理解，该技术最近已被FDA批准用于治疗抑郁症，并有可能带来额外的健康益处。

DESCRIPTION (provided by applicant): What are the mechanisms underlying orientation selectivity? While orientation perception is one of the most extensively studied elements in vision science, much remains unknown about this basic feature of our visual system. The proposed studies couple psychophysics with emerging techniques in cognitive neuroscience to investigate three main questions: (1) What is the source of orientation selectivity? Although orientation processing remains one of the most extensively studied features of the visual system, considerable controversy remains regarding the basic mechanisms underlying this selectivity. In the first experiment, I will use Transcranial Magnetic Stimulation (TMS), a noninvasive tool for temporarily depressing a region of cortical activity, to delimit the source of orientation selectivity in humans. (2) Can orientation selectivity be modulated by states of awareness? In the second experiment, I propose exploring the flexibility of orientation tuning, asking whether an observers' ability to see a stimulus is dictated by our selectivity for that stimulus. I will use binocular rivalry to manipulate the visibility of a stimulus, while psychophysically measuring the bandwidth of orientation selectivity. These results will not only shed light on mechanisms of orientation tuning, but will also reveal a hitherto unexplored aspect of binocular rivalry: the role of selectivity on perceptual states of rivalry. (3) What is the interplay between orientations? In the third experiment, I will investigate the source of an established perceptual illusion: the tilt repulsion effect. It has been suggested that this illusion, which arises from an interaction between different orientation representations, has intracortical origins. I will use TMS, in conjunction with psychophysics, to help isolate the source of this interaction. Upon completion of my training, I plan to pursue a university professorship position researching visual perception, with the goal of linking physiological findings with human behavior. To that end, the broad objective of the proposed studies is to gain expertise with innovative new theoretical and empirical approaches, such as models of orientation selectivity and TMS, allowing me to better establish that link. In addition to improving our understanding of the human visual system, the proposed research stands to provide significant benefits to public health. Studying binocular rivalry is directly relevant to our understanding of visual disorders such as amblyopia, where disparate signals enter the two eyes. Moreover, the proposed studies using TMS will bolster our understanding of a nascent technique, which recently has been FDA approved for treatment of depression, with potential for additional health benefits.