Electrocorticographic studies of human cortical function

描述（由申请人提供）：来自动物和人类的汇聚证据表明，高频伽马带（>30 Hz）活动是大脑中信息处理的重要电生理特征。伽马活动被假设为反映区域皮层处理期间以及跨皮层区域的信息传输和整合期间的神经元同步。从硬膜下电极植入用于临床目的的皮层电图（ECoG）记录，提供了一个不寻常的机会，研究这种活动在人类中更详细。前两个假设进行测试是（1）功能专门的皮层网络内的皮层处理与ECoG伽马活动，（2）皮层处理的选择性注意的自上而下的调制是由ECoG伽马活动的增加反映。此外，据推测，由认知任务所从事的皮层区域之间的功能相互作用反映了他们的ECoG信号之间的时间和频率依赖的相互作用，特别是在伽马波段。最后，假设上述ECoG伽马响应与皮质激活的其他ECoG指数结合，可用于在手术前映射皮质功能。具体目标：（1）阐明功能特化皮层区域激活过程中γ和其他频率的锁相和非锁相反应之间的关系。(2)测试在皮层刺激处理的自上而下调制过程中，选择性注意对局部伽马反应的影响。(3)在皮质网络之间的功能相互作用期间，测试伽马响应和信号传输的频率依赖估计之间的关系。(4)通过与临床皮层电刺激标测进行比较，测试ECoG在功能标测中的实用性。重要性：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，以及开发功能性脑映射的新工具，以最大限度地减少切除性脑手术后的临床损伤。

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.