Functional mapping of human sensorimotor cortex with electrocorticographic spectral analysis - II. Event-related synchronization in the gamma band
Functional mapping of human sensorimotor cortex with electrocorticographic spectral analysis - II. Event-related synchronization in the gamma band
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DOI：
10.1093/brain/121.12.2301
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发表时间：
1998-12-01
期刊：
影响因子：
14.5
通讯作者：
Lesser, RP
中科院分区：
文献类型：
--
作者：
Crone, NE;Miglioretti, DL;Lesser, RP
动物实验表明，“伽马带”（bbb30 Hz）的神经元活动与皮层激活有关，并可能在皮层加工的多区域和多模式整合中发挥作用。人类头皮脑电图的伽马活动研究通常集中在40 Hz频段的事件相关同步（ERS）。为了进一步评估伽马波段ERS，作为皮层激活的指标和人类大脑功能映射的工具，我们记录了5名临床受试者在执行视觉运动决策任务时的硬脑膜下皮质电图（ECoG）信号，这些任务旨在激活感觉运动皮层中不同身体部位的表征。ECoG谱分析采用混合效应分析方差模型，其中考虑了试验内时间依赖性。采用探索性方法，我们研究了30至100 Hz范围内10-Hz宽波段（重叠5 Hz）的伽马ERS，并将这些发现与α (8-13 Hz)和β (15-25 Hz)波段的变化进行了比较。Gamma ERS（在3名受试者中观察到）发生在两个宽波段——“低Gamma”包括35-45和40-50 Hz波段，“高Gamma”包括75-85、80-90、85-95和90-100 Hz波段。低伽马和高伽马ERS的时空特征明显，提示相对独立的神经生理机制。低伽马电激反应通常在运动反应开始后开始，并在大部分时间内持续，与α带的事件相关去同步（ERD）并行。高γ - ERS通常在运动反应期间或稍早于运动反应开始，并且是短暂的，在运动反应完成之前结束。这些低伽马和高伽马的时间差异表明与运动表现的不同功能关联。与α ERD和β ERD相比，低和高γ ERD的地形模式更加离散和体位特异性，并且只发生在单侧肢体运动时的对侧感觉运动皮层（α和β ERD也在同侧观察到）。从伽玛ERS推断的感觉运动功能图与临床目的的皮质电刺激产生的图一致。此外，同一被试在不同的任务条件下产生的运动反应潜伏期和γ - ERS，特别是高γ - ERS的开始潜伏期存在一致的差异。与α ERD和β ERD相比，γ ERD的地形图更符合传统的感觉运动功能解剖图。此外，伽马ERS可能提供关于皮层神经生理学的补充信息，这对绘制人类大脑功能很有用。
It has been shown in animals that neuronal activity in the 'gamma band' (>30 Hz) is associated with cortical activation and may play a role in multi-regional and multi-modal integration of cortical processing. Studies of gamma activity in human scalp EEG have typically focused on event-related synchronization (ERS) in the 40 Hz band. To assess further the gamma band ERS further, as an index of cortical activation and as a tool for human functional brain mapping, we recorded subdural electrocorticographic (ECoG) signals in five clinical subjects while they performed visual-motor decision tasks designed to activate the representations of different body parts in sensorimotor cortex. ECoG spectral analysis utilized a mixed-effects analysis of variance model in which within-trial temporal dependencies were accounted for. Taking an exploratory approach, we studied gamma ERS in 10-Hz-wide bands (overlapping by 5 Hz) ranging from 30 to 100 Hz, and compared these findings with changes in the alpha (8-13 Hz) and beta (15-25 Hz) bands. Gamma ERS (observed in three out of subjects) occurred in two broad bands-'low gamma' included the 35-45 and 40-50 Hz bands, and 'high gamma' the 75-85, 80-90, 85-95 and 90-100 Hz bands. The temporal and spatial characteristics of low and high gamma ERS were distinct, suggesting relatively independent neurophysiological mechanisms. Low gamma ERS often began after onset of the motor response and was sustained through much of it, in parallel with event-related desynchronization (ERD) in the alpha band. High gamma ERS often began during, or slightly before, the motor response and was transient, ending well before completion of the motor response. These temporal differences in low and high gamma suggest different functional associations with motor performance. Compared with alpha and beta ERD, the topographical patterns of low and high gamma ERS were more discrete and somatotopically specific and only occurred over contralateral sensorimotor cortex during unilateral limb movements (alpha and beta ERD were also observed ipsilaterally). Maps of sensorimotor function inferred from gamma ERS were consistent with maps generated by cortical electrical stimulation for clinical purposes. In addition, different task conditions in one subject produced consistent differences in both motor response latencies and onset latency of gamma ERS, particularly high gamma ERS. Compared with alpha and beta ERD, the topography of gamma ERS is more consistent with traditional maps of sensorimotor functional anatomy. In addition, gamma ERS may provide complementary information about cortical neurophysiology that is useful for mapping brain function in humans.