Short-latency median-nerve somatosensory-evoked potentials and induced gamma-oscillations in humans
Short-latency median-nerve somatosensory-evoked potentials and induced gamma-oscillations in humans
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DOI：
10.1093/brain/awn100
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发表时间：
2008-07-01
期刊：
影响因子：
14.5
通讯作者：
Asano, Eishi
中科院分区：
文献类型：
--
作者：
Fukuda, Miho;Nishida, Masaaki;Asano, Eishi
最近的研究表明，皮层γ振荡与各种形式的生理活动密切相关。在本研究中，颅内记录的正中神经体感诱发电位（SEP）和体感诱发的γ振荡的动态变化的三维MR图像上，这些活动的时间和空间特征进行了分析，在10名儿童正在评估癫痫手术。视觉和定量评估显示，短潜伏期SEP和体感诱发的γ振荡主要涉及中央后回，较少涉及中央前回和顶前小叶。在动画电影中很好地描绘了跨中央沟具有相反极性的N20峰的偶极子的形成。高频（100-250 Hz）体感诱发的γ振荡在正中神经刺激后13.6-17.5 ms出现于中央后回，在100 Hz附近及以下频率逐渐减慢，并逐渐累及邻近区域。相当大比例的体感诱发的伽马振荡最初是锁相的，非锁相成分的比例随着时间的推移逐渐增加。皮层刺激证明的主要运动手领域经常与显示最大的N20峰值和最大的体感诱发伽马振荡的网站相吻合。SEP的体内动画和体感诱发的伽马振荡都可以用于在术前评估中定位主要的感觉运动手区域。SEP上的偶极子与先前接受的沿中央沟沿着的皮质被激活的概念一致。在中枢后回的高频体感诱发的γ振荡可能代表外部体感刺激的初始神经处理，而随后的低频振荡可能代表较大的皮层网络中发生的传入皮层活动。
Recent studies have suggested that cortical gamma-oscillations are tightly linked with various forms of physiological activity. In the present study, the dynamic changes of intracranially recorded median-nerve somatosensory-evoked potentials (SEPs) and somatosensory-induced gamma-oscillations were animated on a three-dimensional MR image, and the temporal and spatial characteristics of these activities were analysed in 10 children being evaluated for epilepsy surgery. Visual and quantitative assessments revealed that short-latency SEPs and somatosensory-induced gamma-oscillations predominantly involved the post-central gyrus and less intensely involved the pre-central gyrus and the anterior parietal lobule. Formation of a dipole of N20 peak with opposite polarities across the central sulcus was well delineated in animation movies. High-frequency (100-250 Hz) somatosensory-induced gamma-oscillations emerged in the post-central gyrus at 13.6-17.5 ms after median-nerve stimulation, gradually slowed down in frequency around and below 100 Hz, and progressively involved the neighbouring areas. A substantial proportion of somatosensory-induced gamma-oscillations was initially phase-locked and the proportion of a non-phase-locked component gradually increased over time. The primary motor hand areas proven by cortical stimulation frequently coincided with the sites showing the largest N20 peak and the largest somatosensory-induced gamma oscillations. In vivo animation of SEPs and somatosensory-induced gamma oscillations both may be utilized to localize the primary sensory-motor hand area in pre-surgical evaluation. The dipole on SEPs is consistent with the previously accepted notion that the cortices along the central sulcus are activated. The high-frequency somatosensory-induced gamma-oscillations in the post-central gyrus may represent the initial neural processing for external somatosensory stimuli, whereas the subsequent lower-frequency oscillations might represent the reafferent cortical activity occurring in larger cortical networks.