Methods for Dynamic Functional Imaging

描述（由申请人提供）：感知的基本目标是通过对映射到环境中的结构（如物体和表面）的感官刺激中的时间和空间的解释来推断世界的结构。这个建议的目标是跟踪出现低级别的对象处理操作，因为它们在时间和皮层区域的演变，并研究如何快速，在线学习或适应修改这些反应。我们建议研究的机制，视觉系统分割成对象和表面的视觉场景，以及它如何适应其反应的刺激与不同水平的时间规律性使用组合的EEG源成像和功能性MRI技术在正常成年人。在第一个目标中，我们将研究注意力如何与涉及图形-背景分割的低层次机制相互作用。一种新颖的，多输入的刺激和分析方法将被用来分离反应的数字和他们的背景。在第二个目标中，我们将确定如何时间的可预测性形状的准确性行为的形状歧视相关的行为表现与活动的视觉和控制领域之前发生的可预测的目标。第二个目标是确定是否可以隐式地发生响应于时间规则刺激的预期诱发活动。第三个目标将记录对不同程度的显著性的可预测和不可预测的刺激的反应。预期活动将通过从在刺激显著性范围内用时间规律刺激测量的那些诱发反应中减去源自随机刺激的诱发反应的重建来分离。这些数据将被用来测试的假设，即预期活动产生于前额叶皮层，并产生其最大的影响，在目标地区的枕/枕颞叶皮层的低显着性刺激。公共卫生相关性我们将研究的任务需要整个视觉层次的综合活动，在前额叶皮层的执行控制区和负责感觉运动整合和运动反应的区域。我们开发的将大脑活动和行为在每个层面联系起来的方法将与理解和管理视觉处理，视觉记忆，视觉运动整合和运动执行的障碍有关。由于该方法是非侵入性的，它们可以直接应用于临床人群，在未来的研究皮层视觉障碍，创伤性脑损伤，中风，痴呆和先天性脑畸形。这些疾病经常损害视觉处理，并且每种通常涉及运动和认知功能的显著损害。仔细调整的协议，将在本提案中开发可能会提供相关的信息，这些疾病的诊断和管理。

DESCRIPTION (provided by applicant): The fundamental goal of perception is to infer the structure of the world through an interpretation of temporal and spatial regularities in sensory stimulation that map onto structures in the environment such as objects and surfaces. The goal of this proposal is to trace the emergence of low-level object processing operations as they evolve in time and cortical area and to study how rapid, on-line learning or adaptation modifies these responses. We propose to study the mechanisms by which the visual system segments the visual scene into objects and surfaces and how it adapts its responses to stimuli with varying levels of temporal regularity using a combination of EEG source-imaging and functional MRI techniques in normal adults. In the first Aim we will study how attention interacts with low-level mechanisms involved in figure-ground segmentation. A novel, multi-input stimulation and analysis method will be used to separate response to figures and their backgrounds. In the second Aim, we will determine how temporal predictability shapes the accuracy behavioral shape discrimination by correlating behavioral performance with activity in visual and control areas that occurs before the presentation of predictable targets. A second goal is to determine if anticipatory evoked activity made in response to temporally regular stimuli can occur implicitly. The third Aim will record responses to predictable and unpredictable stimuli of varying degrees of salience. Anticipatory activity will be isolated by subtracting reconstructions of the evoked response derived from random stimuli from those measured with temporally regular stimuli over a range of stimulus salience. These data will be used to test the hypothesis that anticipatory activity is generated in prefrontal cortex and produces its largest effects in target areas of occipital/occipital temporal cortex for low salience stimuli. PUBLIC HEALTH RELEVANCE The tasks we will study require integrated activity throughout the visual hierarchy, in executive control areas of pre-frontal cortex and in areas responsible for sensory motor integration and motor response. The methods we develop to link brain activity and behavior at each of these levels will be relevant to understanding and managing disorders of visual processing, visual memory, visuo-motor integration and motor execution. Because the methods are non-invasive they can be applied directly to clinical populations in future studies of Cortical Visual Impairment, traumatic brain injury, stroke, dementia and congenital brain malformations. These disorders frequently compromise visual processing and each often involves significant compromise of motor and cognitive functions. Careful adaptation of the protocols that will be developed in this proposal may provide information relevant to the diagnosis and management of these disorders.