How Ongoing Neuronal Oscillations Account for Evoked fMRI Variability
How Ongoing Neuronal Oscillations Account for Evoked fMRI Variability
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DOI：
10.1523/jneurosci.0210-11.2011
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发表时间：
2011-07-27
影响因子：
5.3
通讯作者：
Ritter, Petra
中科院分区：
文献类型：
--
作者：
Becker, Robert;Reinacher, Matthias;Ritter, Petra
尽管输入或任务持续不断，但诱发的单审反应的可变性是fMRI记录的大规模脑信号的特征。初始证据表明fMRI信号变异性与感知和行为的相关性。然而，以前尚未证实潜在的内在神经元来源。在这里，我们使用同时的EEG-FMRI和正在进行的α-节律状态的实时分类来解决这个问题，从而触发人类受试者的视觉刺激。我们研究了是否自发性神经元振荡 - 在后α节奏符号中反映了诱发fMRI响应的变异性。基于先前的工作，我们特别假设fMRI活性的线性叠加与正在进行的Alpha节奏的波动和视觉诱发的fMRI响应有关。我们观察到，自发性α-利用功率波动在很大程度上解释了诱发的fMRI反应方差，丘脑外和小脑区域。对于外部区域，我们证实了线性叠加假设。因此，我们将诱发fMRI响应变异性与固有节奏的功率波动联系起来。这些发现有助于我们对脑节律如何在刺激处理中逐审变异的概念理解。
Variability of evoked single-trial responses despite constant input or task is a feature of large-scale brain signals recorded by fMRI. Initial evidence signified relevance of fMRI signal variability for perception and behavior. Yet the underlying intrinsic neuronal sources have not been previously substantiated. Here, we address this issue using simultaneous EEG-fMRI and real-time classification of ongoing alpha-rhythm states triggering visual stimulation in human subjects. We investigated whether spontaneous neuronal oscillations-as reflected in the posterior alpha rhythm-account for variability of evoked fMRI responses. Based on previous work, we specifically hypothesized linear superposition of fMRI activity related to fluctuations of ongoing alpha rhythm and a visually evoked fMRI response. We observed that spontaneous alpha-rhythm power fluctuations largely explain evoked fMRI response variance in extrastriate, thalamic, and cerebellar areas. For extrastriate areas, we confirmed the linear superposition hypothesis. We hence linked evoked fMRI response variability to an intrinsic rhythm's power fluctuations. These findings contribute to our conceptual understanding of how brain rhythms can account for trial-by-trial variability in stimulus processing.