Stimulus-Induced and State-Dependent Sustained Gamma Activity Is Tightly Coupled to the Hemodynamic Response in Humans
Stimulus-Induced and State-Dependent Sustained Gamma Activity Is Tightly Coupled to the Hemodynamic Response in Humans
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DOI：
10.1523/jneurosci.1402-09.2009
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发表时间：
2009-11-04
影响因子：
5.3
通讯作者：
Obrig, Hellmuth
中科院分区：
文献类型：
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作者：
Koch, Stefan P.;Werner, Peter;Obrig, Hellmuth
对刺激的迅速行为反应取决于刺激的显著性以及受试者的准备。因此，刺激属性和认知因素，如注意力，可以确定在伽马范围内的神经元同步的强度。对于通过非侵入性成像的刺激-反应处理的全面调查，然而，这是一个至关重要的问题，是否两种伽马调制引起血流动力学反应。在这里，我们表明，在人类的视觉皮层，刺激强度和内部状态调节持续的伽马活动和血液动力学反应密切对应。当参与者报告对比度不同的光栅速度变化时，伽马活动（35-70 Hz）随着对比度系统性增加。对于恒定对比度的刺激，行为相关的速度变化之前的γ活动的幅度呈负相关的行为反应潜伏期。这表明伽马活动也反映了整体的注意力状态。对于这两种方差来源，伽马活性与通过光学地形测量的血流动力学反应紧密相关。由于高频神经元活动和血液动力学信号之间的密切关系，我们得出结论，刺激诱导的和状态依赖的伽马活动触发代谢需求，并服从于基于血管的成像。
A prompt behavioral response to a stimulus depends both on the salience of the stimulus as well as the subject's preparedness. Thus, both stimulus properties and cognitive factors, such as attention, may determine the strength of neuronal synchronization in the gamma range. For a comprehensive investigation of stimulus-response processing through noninvasive imaging, it is, however, a crucial issue whether both kinds of gamma modulation elicit a hemodynamic response. Here, we show that, in the human visual cortex, stimulus strength and internal state modulate sustained gamma activity and hemodynamic response in close correspondence. When participants reported velocity changes of gratings varying in contrast, gamma activity (35-70 Hz) increased systematically with contrast. For stimuli of constant contrast, the amplitude of gamma activity before the behaviorally relevant velocity change was inversely correlated to the behavioral response latency. This indicates that gamma activity also reflects an overall attentive state. For both sources of variance, gamma activity was tightly coupled to the hemodynamic response measured through optical topography. Because of the close relationship between high-frequency neuronal activity and the hemodynamic signal, we conclude that both stimulus-induced and state-dependent gamma activity trigger a metabolic demand and are amenable to vascular-based imaging.