Synchronization between background activity and visually evoked potential is not mirrored by focal hyperoxygenation: Implications for the interpretation of vascular brain imaging
Synchronization between background activity and visually evoked potential is not mirrored by focal hyperoxygenation: Implications for the interpretation of vascular brain imaging
复制标题
DOI：
10.1523/jneurosci.3989-05.2006
复制
发表时间：
2006-05-03
影响因子：
5.3
通讯作者：
Obrig, H
中科院分区：
文献类型：
--
作者：
Koch, SP;Steinbrink, J;Obrig, H
我们进行了脑电图和光学地形图研究，同时探索电生理和血管反应幅度作为刺激频率的函数。为了引起视觉皮层的反应，受试者被暴露在闪烁频率从1到25 Hz（1 Hz步长，闭上眼睛）。扩展标准视图以比较诱发神经元与诱发血管反应的幅度，我们还研究了α功率的调制，α功率是“背景”EEG活动的标记。结果显示了电生理和血管反应之间的两个差异：（1）当以单独的α频率（IAF）刺激时，VEP和α功率呈现不连续的峰值（类似于10-11 Hz），表明背景振荡和诱发反应之间的共振;这不是血管反应所反映的。（2）相反，血管响应在7- 8Hz处稳定地增加到最大值，并且随着频率的升高而略微降低。这种连续的频率依赖性部分地反映在α功率降低到8-9 Hz的频率和α功率略微增加超过IAF共振。虽然表明α功率和血管反应之间的反比关系，但诱发反应的频率依赖性并不显示这种相关性，因此，个体的α频率和等频率刺激之间的电生理共振并不反映在血管反应中。此外，自发的背景EEG活动是血管反应幅度的重要调制器。我们讨论了这些偏差从一个简单的一对一之间的翻译诱发电位和血管反应振幅的同步，衰减和诱导的背景振荡，如α-节奏的光的问题。
We performed an electroencephalography and optical topography study simultaneously exploring electrophysiological and vascular response magnitude as a function of stimulus frequency. To elicit a response in the visual cortex, subjects were exposed to flicker frequencies varying from 1 to 25Hz (1Hz steps, eyes closed). Extending the standard view to compare magnitudes of the evoked neuronal to the evoked vascular response, we additionally investigated modulations of alpha-power, a marker of "background" EEG activity.The results show two discrepancies between the electrophysiological and vascular response: ( 1) VEP and alpha-power exhibit a discontinuous peak when stimulating at the individual alpha-frequency (IAF) (similar to 10-11 Hz), indicating resonance between background oscillations and evoked response; this is not mirrored by the vascular response. ( 2) The vascular response, in contrast, steadily increases up to a maximum at 7-8 Hz and slightly decreases with higher frequencies. This continuous frequency dependence is partly reflected by the decrease in alpha-power up to frequencies of 8-9 Hz and a slight increase in alpha-power beyond the IAF resonance. Although indicating an inverse relationship between alpha-power and vascular response, the frequency dependence of the evoked response does not show such a correlation.Thus, electrophysiological resonance between an individual's alpha-frequency and isofrequent stimulation is not mirrored by the vascular response. Also, spontaneous background EEG activity is an important modulator of the vascular response magnitude. We discuss these deviations from a simple one-to-one translation between evoked potential and vascular response amplitude in the light of questions concerning synchronization, attenuation, and induction of background oscillations such as the alpha-rhythm.