Where orientation selectivity arises, and how it can change

描述(由申请人提供)：定向选择性背后的机制是什么？虽然方位知觉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然知之甚少。拟议的研究将心理物理学与认知神经科学中的新兴技术结合起来，以调查三个主要问题：(1)定向选择性的来源是什么？虽然定向加工仍然是视觉系统研究最广泛的特征之一，但关于这种选择性背后的基本机制仍存在相当大的争议。在第一个实验中，我将使用经颅磁刺激(TMS)，这是一种非侵入性工具，用于暂时抑制大脑皮质活动区，以界定人类定向选择性的来源。(2)定向选择性能否受到意识状态的调节？在第二个实验中，我建议探索定向调节的灵活性，询问观察者看到刺激的能力是否取决于我们对刺激的选择性。我将使用双眼竞争来操纵刺激的可见度，同时从心理物理上测量定向选择性的带宽。这些结果不仅揭示了定向调节的机制，而且还揭示了双眼竞争的一个迄今未被探索的方面：选择性在竞争感知状态中的作用。(3)取向之间的相互作用是什么？在第三个实验中，我将研究一种已建立的知觉错觉的来源：倾斜排斥效应。有人认为，这种错觉源于不同取向表征之间的相互作用，起源于大脑皮层。我将使用TMS，结合心理物理学，帮助隔离这种相互作用的来源。完成培训后，我计划在大学攻读一个研究视觉感知的教授职位，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门知识，例如定向选择性模型和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，这项拟议的研究还将为公众健康带来重大好处。研究双眼竞争直接关系到我们对弱视等视觉障碍的理解，弱视是指不同的信号进入两只眼睛。此外，使用TMS进行的拟议研究将增强我们对这项新技术的理解，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.