Spatiotemporal Mapping of Visual Evoked cortical Activity and Spatial Attention

应聘者描述(由申请人提供)：应聘者的长期目标是从事认知神经学家的学术生涯，专注于认知过程的执行控制，如注意力、工作记忆和决策，使用脑电、脑磁图和功能磁共振成像作为主要研究工具。培训的目的是获得这些方法的专门知识，特别是它们的结合。候选人将接受该领域专家的指导，指导他们如何使用这些方法以及与视觉感知和选择性注意有关的问题。将提供用于获取和分析EEC、MEG和fMRI数据的设施。该研究计划的目标是开发一种新的视网膜复制受限的信源估计方法，并使用这种新方法来估计多个视觉区域的激活时间进程。用fMRI测量的视网膜定位图和由高分辨率MRI图像构建的表面镶嵌将被用来创建用脑磁图和EEG测量的视觉诱发反应的皮质生成器的逼真、高度详细的模型。信号源估计将受到多个等偏心视野位置处的脑磁图和脑电对刺激的反应的限制。随着刺激位置的改变，给定视觉区域中的等效电流偶极子以功能磁共振视网膜复制数据预测的方式穿过皮质表面。作为对该方法的验证，刺激对比度和空间频率将发生变化。信号源估计的调制将与对相同刺激的事件相关功能磁共振反应的调制进行比较。最后，这一方法将被用来测量选择性空间注意在个别皮质区域的调制的时间分布。此外，早期视觉区域的活动将与注意控制网络中的活动进行比较，注意控制网络包括后顶叶皮质、额叶眼野和背外侧前额叶皮质。预计开发的方法将在未来正常受试者的视觉知觉和注意控制的研究中发挥相当大的作用，并可能为注意缺陷障碍、自闭症谱系障碍和精神分裂症等注意控制障碍的诊断和翻译研究提供一种有价值的、非侵入性的方法。这一职业发展奖将提供必要的多模式脑成像方法培训，以及开发和测试想法的机会，为未来的研究创造战略和基础。

DESCRIPTION (provided by applicant): The candidate's long-term goal is to pursue an academic career as a cognitive neuroscientist with a focus on executive control of cognitive processes such as attention, working memory, and decision making, using EEC, MEG, and fMRI as the primary investigative tools. The purpose of the training is to gain expertise in these methods and in particular their integration. The candidate will be instructed by experts in the field on the use of these methods and on issues related to visual perception and selective attention. Facilities for the acquisition and analysis of EEC , MEG, and fMRI data will be available. The goal of the research plan is to develop a new retinotopy-constrained source estimation method and use this new method to estimate the time courses of activation in multiple visual areas. Retinotopic maps measured with fMRI and surface tesselations constructed from high resolution MRI images will be used to create realistic, highly detailed models of the cortical generators of visual evoked responses measured with MEG and EEG. Source estimates will be constrained by MEG and EEG responses to stimuli at multiple iso-eccentricity visual field locations. As the stimulus location changes, the equivalent current dipole in a given visual area moves across the cortical surface in a way predicted by fMRI retinotopy data. As a validation of this method, stimulus contrast and spatial frequency will be varied. The modulation of source estimates will be compared to the modulation of event-related fMRI responses to the same stimuli. Finally, this method will be used to measure the temporal profile of modulation in individual cortical areas by selective spatial attention. Furthermore, activity in early visual areas will be compared to activity in the attentional control network comprising posterior parietal cortex, frontal eye fields, and dorsolateral prefrontal cortex. It is anticipated that methods developed will be of considerable use in the future study of visual perception and attentional control in normal subjects and may provide a valuable, non-invasive method for the diagnosis and translational study of disorders of attentional control such as attention-deficit disorder, autism spectrum disorders, and schizophrenia. This career development award will provide necessary training in multi-modal brain imaging methods as well as an opportunity to develop and test ideas, creating strategies and foundations for future study.