Resting-State Glutamate and GABA Concentrations Predict Task-Induced Deactivation in the Default Mode Network
Resting-State Glutamate and GABA Concentrations Predict Task-Induced Deactivation in the Default Mode Network
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DOI：
10.1523/jneurosci.1973-13.2013
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发表时间：
2013-11-20
影响因子：
5.3
通讯作者：
Yang, Yihong
中科院分区：
文献类型：
--
作者：
Hu, Yuzheng;Chen, Xi;Yang, Yihong
人脑默认模式网络（DMN）的失活被认为是抑制内源性活动以支持外源性任务相关过程。这种现象具有重要的功能相关性，DMN失活不足与几种神经精神疾病有关。然而，DMN失活的神经化学机制在很大程度上仍然未知。在本研究中，我们测试的假设，主要兴奋性和抑制性神经递质，谷氨酸和GABA，分别与DMN失活。我们使用磁共振波谱测量后扣带皮层/楔前叶（PCC/PCu）的神经递质浓度，DMN的关键组成部分，和功能磁共振成像，以评估DMN失活诱导的n-回工作记忆任务。我们的研究结果表明，谷氨酸和GABA与DMN失活的显着关联。具体而言，高区域GABA浓度的PCC/PCu区域与增强的失活诱导的任务在同一地区，而高谷氨酸浓度与减少失活。此外，GABA和DMN失活之间的关联随着认知负荷的增加而增加。DMN失活的这些神经化学特征可能为更好地理解DMN在正常生理条件下的功能和神经精神疾病中的功能障碍提供新的见解。
Deactivation of the human brain's default mode network (DMN) is regarded as suppression of endogenous activity to support exogenous task-related processes. This phenomenon has important functional relevance and insufficient DMN deactivation has been implicated in several neuropsychiatric disorders. However, the neurochemical mechanism of the DMN's deactivation remains largely unknown. In the present study, we test the hypothesis that the major excitatory and inhibitory neurotransmitters, glutamate and GABA, respectively, are associated with DMN deactivation. We used magnetic resonance spectroscopy to measure neurotransmitter concentrations in the posterior cingulate cortex/precuneus (PCC/PCu), a key component of the DMN, and functional magnetic resonance imaging to evaluate DMN deactivation induced by an n-back working memory task. Our results demonstrate significant associations of glutamate and GABA with DMN deactivation. Specifically, high regional GABA concentration in the PCC/PCu area is associated with enhanced deactivation induced by the task in the same region, whereas high glutamate concentration is associated with reduced deactivation. Furthermore, the association between GABA and DMN deactivation increases with the cognitive loads. These neurochemical characteristics of DMN deactivation may provide novel insights toward better understanding of the DMN's functions under normal physiological conditions and dysfunctions in neuropsychiatric disorders.