Electrocorticographic studies of human cortical function

描述(由申请人提供)：来自动物和人类的综合证据表明，高频伽马频段(&gt；30赫兹)活动是大脑信息处理的重要电生理特征。伽马活动被假设为反映在区域皮质处理期间以及在跨皮质区域的信息传输和整合期间的神经元同步。临床上植入的硬膜下电极的皮层脑电(ECoG)记录为更详细地研究人类的这一活动提供了一个不同寻常的机会。首先要检验的两个假说是：(1)功能专门化皮质网络内的皮质处理与皮层脑电伽马活动有关；(2)选择性注意对大脑皮质加工的自上而下的调制反映在大脑皮质脑电伽马活动的增加上。此外，假设认知任务所涉及的皮质区域之间的功能相互作用反映在它们的皮层脑电信号之间的时间和频率依赖的相互作用，特别是在伽马频段。最后，假设前述皮层脑电伽玛反应与其他皮层激活的皮层脑电指数相结合，可以在手术前用于绘制皮质功能图。具体目的：(1)阐明在功能专门化皮质区域激活过程中伽马和其他频率的锁相和非锁相反应之间的关系。(2)考察自上而下调制皮层刺激加工过程中选择性注意对区域伽马反应的影响。(3)在大脑皮层网络之间的功能性相互作用过程中，伽马反应和信号传输的频率依赖估计之间的测试关系。(4)通过ECoG与临床电刺激标测的比较，验证ECoG在功能标测中的应用价值。意义：从这项研究中获得的基本知识有望促进未来对人脑功能的神经生理学相关性的研究，以及开发新的功能脑图工具，以最大限度地减少脑部切除手术后的临床损害。

DESCRIPTION (provided by applicant): Converging evidence from both animals and humans indicates that high frequency gamma band (>30 Hz) activity is an important electrophysiological signature of information processing in the brain. Gamma activity is hypothesized to reflect neuronal synchronization during regional cortical processing and during the transmission and integration of information across cortical regions. Electrocorticographic (ECoG) recordings from subdural electrodes implanted for clinical purposes, provide an unusual opportunity to study this activity in humans in greater detail. The first 2 hypotheses to be tested are (1) that cortical processing within functionally specialized cortical networks is associated with ECoG gamma activity, and (2) that top-down modulation of cortical processing by selective attention is reflected by an increase of ECoG gamma activity. In addition, it is hypothesized that functional interactions between cortical regions engaged by a cognitive task are reflected by time-and frequency-dependent interactions between their ECoG signals, particularly in the gamma band. Finally, it is hypothesized that the aforementioned ECoG gamma responses, in combination with other ECoG indices of cortical activation, can be used to map cortical function prior to surgery. Specific aims: (1) Elucidate the relationships among phase-locked and non-phase-locked responses in gamma and other frequencies during activation of functionally specialized cortical regions. (2) Test the effect of selective attention on regional gamma responses during top-down modulation of cortical stimulus processing. (3) Test relationships between gamma responses and frequency-dependent estimates of signal transmission during functional interactions between cortical networks. (4) Test the utility of ECoG for functional mapping by comparing it with clinical electrocortical stimulation mapping. Significance: Basic knowledge derived from this research is expected to facilitate future investigations of the neurophysiological correlates of human brain function, as well as the development of new tools for functional brain mapping to minimize clinical impairment following resective brain surgery.