Resting GABA concentration predicts peak gamma frequency and fMRI amplitude in response to visual stimulation in humans
Resting GABA concentration predicts peak gamma frequency and fMRI amplitude in response to visual stimulation in humans
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DOI：
10.1073/pnas.0900728106
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发表时间：
2009-05-19
影响因子：
11.1
通讯作者：
Singh, Krish D.
中科院分区：
文献类型：
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作者：
Muthukumaraswamy, Suresh D.;Edden, Richard A. E.;Singh, Krish D.
人类大脑的功能成像是临床和认知神经科学研究中越来越重要的技术，其中血氧水平依赖（BOLD）反应的功能MRI（fMRI）和神经振荡的脑电图或脑磁图（MEG）记录是最流行的方法。然而，产生这些反应的神经和生理机制，只有部分理解和这些措施中的参与者之间的变异性的来源很少调查。在这里，我们测试的假设，这些神经成像指标的属性是相关的个体水平的皮层抑制相结合的磁共振波谱量化休息GABA浓度在视觉皮层，MEG测量刺激诱导的视觉伽马振荡和功能磁共振成像测量BOLD响应一个简单的视觉光栅刺激。我们的研究结果表明，在不同的个体中，γ振荡频率与视觉皮层中的静息GABA浓度呈正相关（R = 0.68; P< 0.02），BOLD幅度与静息GABA呈负相关（R = -0.64; P < 0.05），γ振荡频率与BOLD反应的幅度呈强负相关（R = -0.88; P < 0.001）。因此，我们的研究结果是支持最近的理论表明，这些功能性神经影像指标依赖于兴奋/抑制平衡在一个人的皮层和功能性成像结果的解释有重要意义，特别是当组间比较在临床研究。
Functional imaging of the human brain is an increasingly important technique for clinical and cognitive neuroscience research, with functional MRI (fMRI) of the blood oxygen level-dependent (BOLD) response and electroencephalography or magnetoencephalography (MEG) recordings of neural oscillations being 2 of the most popular approaches. However, the neural and physiological mechanisms that generate these responses are only partially understood and sources of interparticipant variability in these measures are rarely investigated. Here, we test the hypothesis that the properties of these neuroimaging metrics are related to individual levels of cortical inhibition by combining magnetic resonance spectroscopy to quantify resting GABA concentration in the visual cortex, MEG to measure stimulus-induced visual gamma oscillations and fMRI to measure the BOLD response to a simple visual grating stimulus. Our results demonstrate that across individuals gamma oscillation frequency is positively correlated with resting GABA concentration in visual cortex (R = 0.68; P< 0.02), BOLD magnitude is inversely correlated with resting GABA (R = -0.64; P < 0.05) and that gamma oscillation frequency is strongly inversely correlated with the magnitude of the BOLD response (R = -0.88; P < 0.001). Our results are therefore supportive of recent theories suggesting that these functional neuroimaging metrics are dependent on the excitation/inhibition balance in an individual's cortex and have important implications for the interpretation of functional imaging results, particularly when making between-group comparisons in clinical research.