Investigating Frontoparietal and Occipitotemporal Contributions to Awareness

描述(由申请人提供)： 视觉事件通常不会被注意到，即使它在其他时间很容易被检测到。决定我们是否意识到视觉事件的神经机制是什么？在拟议的一系列实验中，我们计划研究视觉感知的神经基础。特别是，我们提出了一种新的组合，具有高时间和空间分辨率的神经成像和皮质活动的直接扰动来理解额顶叶和枕颞叶皮质之间的相互作用，以服务于视觉感知。因为负责我们最终感知的皮质区域之间的相互作用发生在很短的时间尺度上，所以它们天生就很难绘制出来。事件相关光信号(EROS)的高空间和时间分辨率使我们能够测量这些区域之间的快速相互作用。此外，通过将EROS与单脉冲经颅磁刺激(TMS)相结合，我们不仅可以测量神经对刺激的反应，还可以观察系统对网络中特定节点的扰动(通过TMS)的反应。这些方法将使我们能够确定意识是否依赖于额顶皮质的反馈，以及额顶活动对正在进行的振荡大脑活动的贡献及其对意识的影响。通过这里提出的所有实验，我们将获得有价值的洞察力，了解负责我们视觉体验的额顶和枕颞部机制之间的相互作用。这些知识可能对正常视力和一系列起源于皮质的视觉障碍有影响，如偏盲和视觉失认，以及 为视觉假体的设计提供有价值的信息。更深入地了解额顶叶网络及其与视觉皮质中正在进行的处理的相互作用，也可以为各种与注意力相关的大脑疾病提供洞察力，如注意力缺陷/多动障碍(ADHD)、单侧忽视综合征、阿尔茨海默病、自闭症和精神分裂症。

DESCRIPTION (provided by applicant): A visual event can often go unnoticed, even though it can be readily detected at other times. What are the neural mechanisms that determine whether or not we are aware of a visual event? In the proposed set of experiments we plan to investigate the neural underpinnings of visual awareness. In particular, we propose a novel combination of neuroimaging with high temporal and spatial resolution and direct perturbation of cortical activity to understand the interactions between frontoparietal and occipitotemporal cortex in the service of visual awareness. Because the interactions among cortical areas responsible for our final percept happen on a short time scale, they have been inherently difficult to map out. The high spatial and temporal resolution of the event-related optical signal (EROS) allows us to measure these fast interactions between areas. Furthermore, by combining EROS with single-pulse transcranial magnetic stimulation (TMS) we can not only measure the neural response to stimuli but also observe the response of the system to perturbations (via TMS) of specific nodes in the network. These methods will allow us to determine whether awareness depends on feedback from frontoparietal cortex as well as contribution of frontoparietal activity to ongoing oscillatory brain activity and its influnce on awareness. Across all the experiments proposed here, we will gain valuable insight into the interactions of frontoparietal and occipitotemporal mechanisms responsible for our visual experience. Such knowledge can have implications for normal vision and a range of visual disorders that are cortical in their origin, such as hemianopia and the visual agnosias, as well as provide valuable information for designing visual prostheses. A deeper understanding of the frontoparietal network and its interaction with ongoing processing in visual cortex could also provide insight to a variety of attention-related brain disorders such as Attention Deficit / Hyperactivity Disorder (ADHD), unilateral neglect syndrome, Alzheimer's disease, autism and schizophrenia.