Neural mechanisms of perceptual localization

知觉定位的神经机制

基本信息

批准号：
8819544
负责人：
DAVID V WHITNEY
金额：
$ 36.27万
依托单位：
UNIVERSITY OF CALIFORNIA BERKELEY
依托单位国家：
美国
项目类别：
财政年份：
2007
资助国家：
美国
起止时间：
2007-04-01 至 2017-03-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8819544
关键词：
Accounting Affect Amblyopia Area Ataxia Autistic Disorder Automobile Driving Brain Brain imaging Code Coffee Cognition Disorders Conflict (Psychology)Cues Data Development Diagnostic Dissociation Dyslexia Fragile X Syndrome Functional Magnetic Resonance Imaging Goals Grant Health Impaired cognition Impairment Location Macular degeneration Measurable Measures Modeling Motion Nature Neurologic Optics Outcome Outcome Measure Pattern Play Positioning Attribute Process Psychophysics Retina Retinal Role Schizophrenia Sorting - Cell Movement Staging Stimulus Techniques Testing Time Treatment outcome Update Visual Visual Cortex Visual Motion Visual impairment Visual system structure Walking area V1 base extrastriate visual cortex flexibility insight interest nervous system disorder neuromechanism novel predictive marker relating to nervous system research study retinotopic spatiotemporal tool visual motor visual process visual processing

项目摘要

DESCRIPTION (provided by applicant): Virtually every visual and visuomotor function hinges first and foremost on the visual system's ability to consistently and accurately localize stimuli, and this is especially true in cluttered and dynamic scenes. However, it is unknown what sorts of information are integrated to determine perceived position, how such integration occurs, or what the neural mechanism(s) and loci of this process are. Perceptual localization in typically cluttered and dynamic scenes requires the visual system to both assign and update object positions; to do this it relies not just on the retinal location of the object of interest, but als principally on four additional factors: visual motion, frames of reference, eccentricity biases, an contrast adaptation. To understand how the visual system assigns and updates object positions, we must approach the task of localization not as an isolated process, but as an integrative one-one that depends on contextual information in the scene. Our proposed experiments have two goals; first, to psychophysically measure perceived position as a function of retinal position, contrast adaptation, visual motion, eccentricity bias, and frames of reference in order to generate a novel multifactorial integration field model; we will use this model in fMRI experiments to test the hypothesis that neurotopic organization across visual cortex is heterogeneous (unique position codes in each visual area) or homogeneous (identical across visual areas). Our pilot results suggest that there are unique position codes in different visual areas. The second goal of the proposal is to test whether these unique position codes (the differences in topographic organization) have perceptual consequences. We will use psychophysics to test these predicted double dissociations in perceived location and then use TMS to test the causal contribution of heterogeneous visual cortical topographic organization to perceived position. One novelty of our approach lies in developing a new mixed generative and discriminative model of spatial coding, that can be applied to psychophysical and fMRI data in tandem, and further allows us to make predictions from fMRI results about perceptual outcomes in specific situations. The causal relationship between fMRI results and perceptual outcomes will then be tested with TMS. Our experiments will provide novel insight on how cues are integrated to determine perceived position at each stage of visual processing, which is crucial to understanding the fundamental localization deficits that occur in a range of visual and cognitive impairments ranging from amblyopia and macular degeneration, to autism. Until we understand how position is assigned in the typical brain, we lack the necessary insight to develop diagnostic tools, predictive markers, and treatment outcome measures for these impairments.

描述（由申请人提供）：实际上，每个视觉和视觉运动功能首先都取决于视觉系统始终如一，准确定位刺激的能力，而在混乱且动态的场景中尤其如此。但是，尚不清楚哪些信息已集成以确定感知的位置，这种整合的发生方式或该过程的神经机制和基因座是什么。通常在混乱和动态场景中的感知定位需要视觉系统来分配和更新对象位置。为此，它不仅依赖于感兴趣的对象的视网膜位置，还依赖于四个其他因素：视觉运动，参考框架，偏心偏见，对比度适应。要了解视觉系统如何分配和更新对象位置，我们必须将本地化任务不是作为一个孤立的过程，而是作为一个依赖场景上下文信息的综合单一过程。我们提出的实验有两个目标。首先，要在心理物理上测量视网膜位置，对比度适应，视觉运动，偏心偏置和参考框架的函数，以生成一种新颖的多因素整合场模型；我们将在fMRI实验中使用该模型来检验以下假设：跨视觉皮层的神经组织是异质的（每个视觉区域中的独特位置代码）或同质性（在视觉区域相同）。我们的试点结果表明，不同视觉区域有独特的位置代码。该提案的第二个目标是测试这些独特的位置代码（地形组织的差异）是否具有感知后果。我们将使用心理物理学在感知的位置测试这些预测的双重分离，然后使用TMS测试异质视觉皮质地形组织对感知位置的因果关系。我们方法的一种新颖性在于开发一种新的混合生成和歧视性空间编码模型，该模型可以应用于串联的心理物理和fMRI数据，并进一步使我们能够从特定情况下的知名度结果进行fMRI的结果。 FMRI结果与感知结果之间的因果关系将通过TMS测试。我们的实验将提供有关如何整合提示以确定视觉处理阶段感知位置的新见解，这对于理解在视觉和认知障碍中发生的基本定位缺陷至关重要。在我们了解如何在典型大脑中分配位置之前，我们缺乏开发这些障碍的诊断工具，预测标记和治疗结果指标的必要见解。