Neurophysiology of Multisensory Integration

描述（由申请人提供）：不同的感官对物理物体的独特方面进行采样，应该为大脑提供更丰富的物体描述，以及关于物体位置、身份和运动的聚合证据。尽管已经对猫的上丘的多感觉处理进行了详细的解释，并且对非人类灵长类动物的多感觉大脑区域进行了详细的解释，但我们对来自不同感觉系统的信息如何在人类新皮层中组合只有初步的了解。本研究的目的是通过结合使用事件相关电位（ERP）记录和功能成像（fMRI）来进一步了解人类皮层多感觉统合。从128个头皮电极记录的erp高密度映射，将这些映射与个体受试者的mri衍生解剖结构共同注册，以及对表面记录数据的来源分析，将使我们能够评估参与这种整合的大脑区域。平行的功能磁共振实验将使我们能够精确地定义与给定的多感官操作有关的大脑区域。ERP源分析和fMRI数据的整合将提供多感觉整合的时空动态。至关重要的是，ERP的精确时间分辨率将使我们能够评估相对于正在进行的单感觉处理的多感觉整合效应的时间过程。我们建议确定：1)双感觉视听刺激中各感觉成分间的时间分离参数对双感觉刺激相关ERP相互作用的影响，2)双感觉刺激的空间分离是否会改变双感觉刺激相关ERP早期相互作用，3)自上而下的影响（注意）是否会影响双感觉刺激的早期多感觉相互作用。4)评估完全与任务无关的感觉模态（视觉）同时刺激对ERP与第二任务相关的感觉模态（某些知觉）相互作用的影响。具体而言，我们希望评估不相关模态在与任务相关的空间信息相矛盾或证实时的影响；5)同时呈现听觉刺激所引起的视觉表观运动知觉的虚幻变化，是否是视觉运动加工区域听觉驱动的加工变化的结果。通过这些研究，我们将开始探索“绑定”过程背后的神经机制，即不同感觉模式之间的相关输入。

DESCRIPTION (provided by applicant): That the different senses sample unique aspects of physical objects should provide the brain with both a richer description of objects, and converging evidence concerning their position, identity and movement. Although there has been a detailed explication of multi sensory processing in the superior colliculus of cats and a number of multi sensory brain regions have been detailed in non-human primates, we have only a rudimentary understanding of how information from different sensory systems is combined in the human neo-cortex. The purpose of this proposal is to further our understanding of human cortical multi sensory integration through the combined use of event-related potential (ERP) recordings and functional imaging (fMRI). High-density mapping of ERPs recorded from 128 scalp electrodes, co-registration of these maps with individual subject MRI-derived anatomy, and source analysis of the surface recorded data will allow us to assess the brain regions involved in such integrations. Parallel fMRI experiments will allow us to precisely define the brain regions involved in a given multi sensory operation. Integration of ERP source-analyses and fMRI data will provide the spatio-temporal dynamics of multi sensory integration. Critically, the precise temporal resolution of the ERP will allow us to assess the time-course of multi sensory integration effects relative to the time-course of ongoing unisensory processing. We propose to determine: 1) the temporal separation parameters between the unisensory constituents of a bi-sensory audio-visual stimulus that result in modifications of the ERP interactions associated with bi-sensory stimulation, 2) whether spatial separation of bi-sensory stimuli modifies the early ERP interactions associated with bi-sensory stimulation, 3) whether top-down influences (attention) can effect the earliest multi-sensory interactions to bi-sensory stimulation, 4) to assess the effects of simultaneous stimulation in an entirely task-irrelevant sensory modality (vision) upon the ERP interactions with a second task-relevant sensory modality (somesthesis). Specifically, we wish to assess the effects of the irrelevant modality when it either contradicts or confirms task-relevant spatial information, 5) whether illusory changes in the perception of visual apparent motion, which are induced by presentation of simultaneous auditory stimuli, are the result of auditorily driven processing changes in visual motion processing areas. Through these studies, we will begin to explore the neural mechanisms underlying the process of "binding," related inputs across the separate sensory modalities.