Where orientation selectivity arises, and how it can change

描述（由申请人提供）：取向选择性的机制是什么？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)定向选择性的来源是什么？虽然定向加工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，来划定人类定向选择的来源。(2)定向选择性是否可以被意识状态调节？在第二个实验中，我建议探索方向调整的灵活性，询问观察者看到刺激的能力是否由我们对刺激的选择性决定。我将使用双眼竞争来操纵刺激的可见性，同时从心理物理角度测量定向选择的带宽。这些结果不仅揭示了定向调节的机制，而且还揭示了迄今为止双目竞争的一个未被探索的方面：选择性在竞争的感知状态中的作用。(3)取向之间的相互作用是什么？在第三个实验中，我将研究一个已建立的感知错觉的来源：倾斜排斥效应。有人认为，这种错觉是由不同方向表征之间的相互作用产生的，它有皮层内的起源。我将使用经颅磁刺激，结合心理物理学，来帮助分离这种相互作用的来源。在完成我的训练后，我计划攻读一个研究视觉感知的大学教授职位，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业知识，例如定向选择性模型和经颅磁刺激，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众健康提供重大好处。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，使用经颅磁刺激的拟议研究将加强我们对一种新兴技术的理解，该技术最近已被FDA批准用于治疗抑郁症，具有潜在的额外健康益处。

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.