Nonuniform high-gamma (60-500 Hz) power changes dissociate cognitive task and anatomy in human cortex.
Nonuniform high-gamma (60-500 Hz) power changes dissociate cognitive task and anatomy in human cortex.
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非均匀的高γ（60-500 Hz）功率改变了人皮层中的认知任务和解剖结构。
DOI：
10.1523/jneurosci.4722-10.2011
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发表时间：
2011-02-09
期刊：
影响因子：
--
通讯作者：
Leuthardt EC
中科院分区：
文献类型：
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作者：
Gaona CM;Sharma M;Freudenburg ZV;Breshears JD;Bundy DT;Roland J;Barbour DL;Schalk G;Leuthardt EC
皮质电生理学中的高伽马波段（> 60 Hz）功率变化是局灶性事件相关皮质活动的可靠指标。尽管在细胞水平的振荡阈下和同步阈上活动的发现，有一个越来越流行的观点，高伽玛波段振幅的变化记录从细胞合奏的异步发射活动，产生宽带和均匀的功率增加的结果。其他人已经证明了在低和高伽马波段的功率变化的独立性，但到目前为止，没有研究表明60 Hz以上的任何这种独立性。基于皮层电图（ECoG）信号时频分析的不均匀性，我们假设诱导的高γ波段（60- 500 Hz）功率变化比目前所了解的更不均匀。使用6名人类受试者的单字重复任务，我们发现不同ECoG高伽马子带的功能反应可以区分认知任务（例如，听觉、阅读、说话）和皮层位置。高伽马范围的这些子带中的功率变化在单次试验中始终存在，并且在试验结构中具有统计学上不同的时间过程。此外，当在三个任务相关的解剖区域（感觉运动区、布罗卡区和上级颞回）内的所有受试者之间进行整合时，这些行为和位置依赖性功率变化证明了整个人群的不一致趋势。总而言之，在很大的频率范围内功率变化的独立性和不均匀性表明，有必要采用一种新的方法来评估高γ频带皮质活动。这些发现表明，除了时间和位置，频率是高伽马动力学的另一个基本维度。
High-gamma band (>60Hz) power changes in cortical electrophysiology are a reliable indicator of focal, event-related cortical activity. In spite of discoveries of oscillatory subthreshold and synchronous suprathreshold activity at the cellular level, there is an increasingly popular view that high-gamma band amplitude changes recorded from cellular ensembles are the result of asynchronous firing activity that yields wideband and uniform power increases. Others have demonstrated independence of power changes in the low- and high-gamma bands, but to date, no studies have shown evidence of any such independence above 60Hz. Based on non-uniformities in time-frequency analyses of electrocorticographic (ECoG) signals, we hypothesized that induced high-gamma band (60-500Hz) power changes are more heterogeneous than currently understood. Using single-word repetition tasks in six human subjects, we showed that functional responsiveness of different ECoG high-gamma sub-bands can discriminate cognitive task (e.g., hearing, reading, speaking) and cortical locations. Power changes in these sub-bands of the high-gamma range are consistently present within single trials and have statistically different time courses within the trial structure. Moreover, when consolidated across all subjects within three task-relevant anatomic regions (sensorimotor, Broca's area, and superior temporal gyrus), these behavior- and location- dependent power changes evidenced nonuniform trends across the population. Taken together, the independence and nonuniformity of power changes across a broad range of frequencies suggest that a new approach to evaluating high-gamma band cortical activity is necessary. These findings show that in addition to time and location, frequency is another fundamental dimension of high-gamma dynamics.