Responsiveness of Human Cortical Activity to Rhythmical Stimulation: A Three-Modality, Whole-Cortex Neuromagnetic Investigation
Responsiveness of Human Cortical Activity to Rhythmical Stimulation: A Three-Modality, Whole-Cortex Neuromagnetic Investigation
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人类皮质活动对节律刺激的反应：三模态、全皮质神经磁学研究
DOI：
10.1006/nimg.1998.0323
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发表时间：
1998
期刊：
影响因子：
5.7
通讯作者：
Riitta Hari
中科院分区：
文献类型：
--
作者：
L. Narici;K. Portin;R. Salmelin;Riitta Hari;Riitta Hari
我们开发了数字指标，以量化刺激相关的变化，皮层磁信号记录从9名健康受试者，而他们收到1至2.5秒的列车15个刺激（体感，视觉，或听觉在单独的运行）的速度从6到14赫兹，与1.6秒的停顿。锁定指数（L）被引入到量化的反应是如何锁定的刺激和全球变化因子（GC），以表明在5- 25-Hz的频率范围内的整个皮层振荡活动的变化。反应可视化与颜色编码的图像，说明皮质反应的所有刺激率同时进行。这些彩色图清楚地表明，在训练过程中，特定于模态的皮层信号在对应于刺激速率的频率处得到增强。对于体感刺激，在体感手区附近的活动在大多数刺激率下增强，这主要是诱发反应的叠加。在具有强后部静息节律的个体中，视觉刺激通常以接近自发活动的主频率的刺激率在顶枕沟中夹带活动，这可能反映了内在皮质节律的驱动，而在具有小自发顶枕节律的受试者中，皮质信号似乎主要由视觉诱发反应组成。在听觉刺激期间未观察到模态特异性增强。在列车之间的停顿期间，与静息状态相比，皮层信号被显著抑制：峰值活动（7-13 Hz）在特定模态区域内被调制，但也在特定模态区域外被调制，并且最大功率的频率峰值之外的信号在整个皮层上被所有刺激一致且可再现地抑制。
We developed numerical indicators to quantify stimulus-related changes in cortical magnetic signals recorded from nine healthy subjects while they received 1- to 2.5-s trains of 15 stimuli (somatosensory, visual, or auditory in separate runs) at rates from 6 to 14 Hz, intermingled with 1.6-s pauses. A locking index (L) was introduced to quantify how well the responses are time locked to the stimuli and a global change factor (GC) to indicate changes in the whole-cortex oscillatory activity in the 5- to 25-Hz frequency range. The responses were visualized with color-coded images illustrating cortical reactivity for all stimulus rates simultaneously. These color maps clearly showed that the modality-specific cortical signals were enhanced at frequencies corresponding to the stimulus rate during the trains. For somatosensory stimulation the activity in the vicinity of the somatosensory hand area was enhanced at most stimulus rates, suggesting mainly superposition of evoked responses. In individuals with strong posterior resting rhythm, visual stimuli typically entrained activity in the parietooccipital sulcus at stimulus rates close to the main frequency of the spontaneous activity, probably reflecting driving of the intrinsic cortical rhythm, whereas in subjects with little spontaneous parietooccipital rhythm the cortical signal appeared to be composed mainly of visual evoked responses. No modality-specific enhancement was observed during auditory stimulation. During the pauses between the trains, the cortical signals were significantly suppressed compared with the resting condition: The peak activity (7-13 Hz) was modulated within, but also outside, the modality-specific areas, and the signals outside the frequency peaks of maximum power were consistently and reproducibly suppressed over the whole cortex by all stimuli.