Wyss Christine, Tse Desmond H Y, Kometer Michael, Dammers Jürgen, Achermann Rita, Shah N Jon, Kawohl Wolfram, Neuner Irene
Department of Psychiatry, Psychotherapie and Psychosomatics, Hospital of Psychiatry, University of Zurich, Switzerland.
Institute of Neuroscience and Medicine, INM4, Forschungszentrum Jülich, Germany.
Hum Brain Mapp. 2017 Aug;38(8):3975-3987. doi: 10.1002/hbm.23642. Epub 2017 May 8.
Gamma-aminobutyric acid (GABA) and glutamate are believed to have inhibitory and exhibitory neuromodulatory effects that regulate the brain's response to sensory perception. Furthermore, frequency-specific synchronization of neuronal excitability within the gamma band (30-80 Hz) is attributable to a homeostatic balance between excitation and inhibition. However, our understanding of the physiological mechanism underlying gamma rhythms is based on animal models. Investigations of the relationship between GABA concentrations, glutamate concentrations, and gamma band activity in humans were mostly restricted to the visual cortex and are conflicting. Here, we performed a multimodal imaging study combining magnetic resonance spectroscopy (MRS) with electroencephalography (EEG) in the auditory cortex. In 14 healthy subjects, we investigated the impact of individual differences in GABA and glutamate concentration on gamma band response (GBR) following auditory stimulus presentation. We explored the effects of bulk GABA on the GBR across frequency (30-200 Hz) and time (-200 to 600 ms) and found no significant relationship. Furthermore, no correlations were found between gamma peak frequency or power measures and metabolite concentrations (GABA, glutamate, and GABA/glutamate ratio). These findings suggest that, according to MRS measurements, and given the auditory stimuli used in this study, GABA and glutamate concentrations are unlikely to play a significant role in the inhibitory and excitatory drive in the generation of gamma band activity in the auditory cortex. Hum Brain Mapp 38:3975-3987, 2017. © 2017 Wiley Periodicals, Inc.
γ-氨基丁酸（GABA）和谷氨酸被认为具有抑制性和兴奋性神经调节作用，可调节大脑对感觉感知的反应。此外，γ波段（30 - 80赫兹）内神经元兴奋性的频率特异性同步归因于兴奋与抑制之间的稳态平衡。然而，我们对γ节律潜在生理机制的理解基于动物模型。对人类GABA浓度、谷氨酸浓度与γ波段活动之间关系的研究大多局限于视觉皮层，且结果相互矛盾。在此，我们在听觉皮层进行了一项将磁共振波谱（MRS）与脑电图（EEG）相结合的多模态成像研究。在14名健康受试者中，我们研究了GABA和谷氨酸浓度的个体差异对听觉刺激呈现后γ波段反应（GBR）的影响。我们探讨了整体GABA对跨频率（30 - 200赫兹）和时间（-200至600毫秒）的GBR的影响，未发现显著关系。此外，在γ峰值频率或功率测量与代谢物浓度（GABA、谷氨酸和GABA/谷氨酸比值）之间未发现相关性。这些发现表明，根据MRS测量结果，并鉴于本研究中使用的听觉刺激，GABA和谷氨酸浓度在听觉皮层γ波段活动产生的抑制性和兴奋性驱动中不太可能发挥重要作用。《人类大脑图谱》38:3975 - 3987，2017年。© 2017威利期刊公司。
