Neural mechanisms of shape perception

描述（由申请人提供）：视力是我们幸福的重要组成部分。然而，允许在视觉对象的位置变化下稳定感知视觉对象的神经机制还没有得到充分的理解。特别是，我们目前缺乏具体的知识，神经反应是如何在腹侧视觉通路中进行视觉物体识别的转换。在这里，我们建议探测神经元的视觉区域V2和V4内的腹侧通路与自然的刺激，以系统地确定他们的刺激选择性偏好。自然刺激提供了一个系统的方法来研究神经功能的选择性，因为它们引起强大的反应，从神经元在视觉处理的所有阶段，因为它们构成了一个刺激集，是不依赖于一个特定的假设普遍的神经功能的选择性。我们最近开发的统计方法，允许的特征选择性的神经元，探测与自然刺激的表征，并考虑到神经反应的非线性方面。扩展这些方法来解释这样一个事实，即纹外视觉区的神经元的反应可以容忍刺激位置的变化（目的1）将允许这些神经元在自然条件下的刺激偏好的系统表征。每个神经元的反应将根据与神经反应最相关的两个局部刺激特征来表征。这将提供对视觉场景中被认为发生在V4响应中的弯曲元素的选择性的直接测量（目的2）。最后，我们将测试神经特征选择性的特定参数，如方向和曲率，是否决定了对物体位置变化的容忍度增加的方向（目标3）。了解健康神经系统中形状感知的神经机制是开发有效治疗神经系统疾病的关键因素，例如感知失认症，其中视觉物体识别受损。公共卫生相关性：这项研究将阐明负责形状感知的神经机制。这些神经过程在影响视力的几种神经系统疾病中被破坏。了解健康神经系统中形状感知的神经机制是开发有效治疗视觉物体识别受损的神经系统疾病的关键因素。

Description (provided by applicant): Vision is an essential part of our well-being. Yet, the neural mechanisms allowing for the stable perception of visual objects under variations in their position are not sufficiently understood. In particular, we currently lack specific knowledge of how neural responses are transformed in the ventral visual pathway where visual object recognition is performed. Here we propose to probe neurons in visual areas V2 and V4 within the ventral pathway with natural stimuli in order to systematically determine their stimulus selectivity preferences. Natural stimuli offer a systematic way to study neural feature selectivity because they elicit robust responses from neurons at all stages of visual processing and because they constitute a stimulus set that is not tied to a particular hypothesis about prevalent neural feature selectivity. We have recently developed statistical methods that allow the characterization of the feature selectivity of neurons that are probed with natural stimuli, and which take into account nonlinear aspects of neural responses. Extending these methods to account for the fact that the responses of neurons in extrastriate visual areas can be tolerant to shifts in stimulus position (aim 1) will allow the systematic characterization of the stimulus preferences of these neurons under natural conditions. Responses of each neuron will be characterized according to the two localized stimulus features that are most relevant for the neural responses. This will provide a direct measure of the selectivity to curved elements in visual scenes thought to occur in V4 responses (aim 2). Finally, we will test whether specific parameters of neural feature selectivity, such as orientation and curvature, determines the directions of increased tolerance to shifts in object position (aim 3). Understanding the neural mechanisms of shape perception in the healthy nervous system is a key element in developing effective therapies for neurological disorders, such as apperceptive agnosia, where visual object recognition is impaired. PUBLIC HEALTH RELEVANCE: This study will elucidate the neural mechanisms responsible for shape perception. These neural processes are disrupted in several neurological disorders affecting vision. Understanding the neural mechanisms of shape perception in the healthy nervous system is a key element of developing effective therapies for neurological disorders where visual object recognition is impaired.