ELECTROPHYSIOLOGICAL STUDIES OF HUMAN ATTENTION

描述（由申请人提供）：神经影像学研究提供了大量关于在认知任务期间活跃的人脑皮层和皮层下区域的信息。最近的研究表明，在任务期间被共同激活的区域即使在休息时也保持着高水平的区域间相关性或“功能连接性”。然而，这些区域间的相关性是在长时间尺度（例如分钟）上测量的。相比之下，我们对这些大脑区域在短时间尺度（例如秒或毫秒）内的时间动态和相互作用知之甚少，而这些时间尺度是大多数任务的典型特征。时间动力学和相互作用的分析受到神经成像方法（功能性磁共振成像，fMRI;正电子发射断层扫描，PET）的低时间分辨率和记录颅外电磁活动的方法（脑电图，EEG，脑磁图，MEG）的低空间分辨率的强烈限制。为了解决这些根本的局限性，我们结合了fMRI测量血氧水平依赖（BOLD）信号与皮层脑电图（ECoG）信号记录从侵入性监测人类受试者。我们已经开发出的方法，共同注册功能网络与功能磁共振成像与颅内电极，记录表面皮层局部场电位（LFP）。我们已经应用这些新的方法来研究空间注意的皮质网络的动态和相互作用。我们的初步研究结果表明，在空间注意任务中，皮层网络与功能磁共振成像观察到多种相干调制与ECoG。空间注意力的维持与跨多个枕叶、顶叶和额叶任务相关区域的δ频带（1-3 Hz）中的持续相位同步相关，而空间注意力的转移与θ频带（3-7 Hz）中的相位同步的瞬时增加相关。我们提出了一系列的实验中，我们首先定位与功能磁共振成像皮层区域/网络专门的空间注意，然后研究其动态和相互作用的ECoG的良好特征的认知任务。我们的第一个具体目标是确定的作用，δ/θ波段相位同步连接皮层区域在自愿定向的空间注意。我们的第二个具体目标研究如何三角洲/θ波段相位同步的时间结构的任务的影响。我们的第三个具体目标集中在两个不同的注意网络（背侧，DAN;腹侧，货车）之间的相互作用，在刺激驱动的重定向。

DESCRIPTION (provided by applicant): Neuroimaging studies have provided a wealth of information on the cortical and subcortical regions of the human brain active during cognitive tasks. Recent studies have shown that regions that are co-activated during tasks maintain, even at rest, a high level of inter-regional correlation, or 'functional connectivity'. However, these interregional correlations are measured over long time scales (e.g. minutes). In contrast, little is known about the temporal dynamics and interactions of these brain regions over the short timescales (e.g. sec or ms) that are typical of most tasks. The analysis of temporal dynamics and interactions is strongly limited by the low temporal resolution of neuroimaging methods (functional magnetic resonance imaging, fMRI; Positron emission tomography, PET), and the low spatial resolution of methods for recording extracranial electro-magnetic activity (electroencephalography, EEG, magnetoencephalography, MEG). To solve these fundamental limitations, we have combined fMRI measures of blood-oxgyenation-level- dependent (BOLD) signals with electrocorticographic (ECoG) signals recorded from invasively monitored human subjects. We have developed methods to co-register functional networks localized with fMRI with intracranial electrodes that record surface cortical local field potentials (LFP). We have applied these novel methods to study the dynamics and interactions of cortical networks involved in spatial attention. Our preliminary results indicate that cortical networks observed with fMRI during a spatial attention task show multiple coherence modulations with ECoG. Maintenance of spatial attention correlates with sustained phase synchronization in the delta band (1-3 Hz) across multiple occipital, parietal, and frontal task-relevant regions, while shifts of spatial attention are associated with transient increases of phase synchronization in the theta band (3-7 Hz). We propose a series of experiments in which we first localize with fMRI cortical regions/networks specialized for spatial attention and then study their dynamics and interaction with ECoG on well- characterized cognitive tasks. Our first specific aim is to determine the role of delta/theta band phase synchronization in linking cortical regions during voluntary orienting of spatial attention. Our second specific aim studies how delta/theta band phase synchronization is affected by the temporal structure of a task. Our third specific aims focuses on the interaction between two different attention networks (dorsal, DAN; ventral, VAN) during stimulus-driven re-orienting.