LOCALIZING OBJECTS IN DYNAMIC SCENES

定位动态场景中的对象

• 批准号: 7796603
• 负责人: DAVID V WHITNEY
• 金额: $ 37.41万
• 依托单位: UNIVERSITY OF CALIFORNIA BERKELEY
• 依托单位国家: 美国
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-04-01 至 2012-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7796603
• 关键词: Ataxia; Autistic Disorder; Brain imaging; Code; Data; Dependence; Diagnostic; Dyslexia; Environment; Eye; Feedback; Functional Magnetic Resonance Imaging; Future; Goals; Hand; Impairment; Link; Location; Measures; Modeling; Motion; Nature; Neural Pathways; Optics; Pattern; Play; Positioning Attribute; Process; Property; Psychophysics; Psychophysiology; Research Personnel; Resolution; Retina; Retinal; Role; Schizophrenia; Testing; Therapeutic; Transcranial magnetic stimulation; Update; Visual; Visual Motion; Visual system structure; area V1; base; extrastriate visual cortex; feeding; insight; nervous system disorder; neuromechanism; programs; relating to nervous system; research study; response; retinotopic; tool; visual motor; visual process; visual processing

DESCRIPTION (provided by applicant): Most visual and visuomotor functions hinge on our visual system's ability to localize objects in dynamic scenes-to determine the positions of objects as we move or as objects in the world move around us. However, dynamic localization requires that the visual system must be able to both assign and update object positions, and it remains unclear which visual areas play these necessary roles and what mechanisms are responsible. Assigning and updating object locations is especially relevant considering that the eye is rarely stabilized and objects are constantly drifting across the retina as they move. Given the sluggish nature of visual processing, how do we perceive the positions of moving objects with clarity and precision? To understand how the visual system assigns and updates object positions, we must approach the task of localization not as a static process, but as a dynamic one. The goal of our proposed experiments is to characterize the neural pathways and mechanisms that determine perceived position in dynamic situations. Our preliminary results suggest that two mechanisms are required to perceive the positions of objects when motion is present on the retina: trailing edge deblurring and edge-shifting. Without these mechanisms, we would perceive the world as a blurry smear, unable to accurately predict the future locations of objects or interact with them as they move around us. We hypothesize that these two independent mechanisms integrate information between early visual areas (V1) and the motion sensitive region (MT+). Our pilot data for the proposed experiments suggest that (1) MT+ carries precise information about object position, supporting the hypothesis that it serves an integral role in object localization, and (2) feedback as well as feed-forward connections between V1 and MT+ may be necessary to assign and update the positions of objects when retinal motion is present. Using functional magnetic resonance imaging (fMRI), transcranial magnetic stimulation (TMS), and psychophysics, we will characterize and isolate the neural locus of the two mechanisms and establish their causal roles in perceiving object position. Dynamic localization is the default situation faced by the visual system, but many neurological disorders produce specific deficits in dynamic visual and visuomotor localization, including optic ataxia, dyslexia, akinetopsia, autism, and schizophrenia, among others. Until we understand how position is determined in the normal brain for images that are constantly moving across the retina, we lack the necessary insight to develop diagnostic tools, predictive markers, and therapies for these impairments.

描述（由申请人提供）：大多数视觉和视觉运动函数都取决于我们视觉系统在动态场景中定位对象的能力，以确定我们移动或作为世界上的对象的位置，以确定对象的位置。但是，动态定位要求视觉系统必须能够分配和更新对象位置，并且尚不清楚哪些视觉区域扮演这些必要的角色以及哪些机制负责。考虑到眼睛很少稳定，并且对象在移动时不断遍布视网膜，分配和更新对象位置尤为重要。鉴于视觉处理的性质缓慢，我们如何以清晰和精确的态度感知移动对象的位置？要了解视觉系统如何分配和更新对象位置，我们必须将本地化的任务当作静态过程，而是作为动态过程。我们提出的实验的目的是表征确定动态情况下感知位置的神经途径和机制。我们的初步结果表明，需要两种机制来感知在视网膜上运动时物体的位置：尾边脱毛和边缘转移。没有这些机制，我们将把世界视为模糊的涂片，无法准确预测对象的未来位置或在它们周围移动时与它们互动。我们假设这两种独立的机制将早期视觉区域（V1）和运动敏感区域（MT+）之间的信息整合在一起。我们针对拟议实验的试点数据表明，（1）MT+具有有关对象位置的精确信息，支持了以下假设，即它在对象定位中起着不可或缺的作用，（2）反馈以及V1和MT+之间的反馈以及在存在视网膜运动时分配和更新对象的位置可能是必需的。使用功能磁共振成像（fMRI），经颅磁刺激（TMS）和心理物理学，我们将表征和隔离两种机制的神经基因座，并在感知的对象位置中建立其因果关系。动态定位是视觉系统所面临的默认情况，但是许多神经系统疾病会在动态视觉和视觉运动定位中产生特定的缺陷，包括视觉性共济失调，阅读障碍，Akinetopsia，自闭症，自闭症和精神分裂症等。除非我们了解如何在不断在视网膜上移动的图像中确定正常大脑的位置，否则我们缺乏开发这些障碍的诊断工具，预测标记和疗法的必要见解。