Department of Neurology, The Royal Melbourne Hospital, Victoria, Australia.
Department of Medicine and Radiology, The University of Melbourne, Victoria, Australia.
PLoS One. 2020 Dec 29;15(12):e0244491. doi: 10.1371/journal.pone.0244491. eCollection 2020.
The default mode network (DMN) is the main large-scale network of the resting brain and the PCC/precuneus is a major hub of this network. Glutamate and GABA (γ-amino butyric acid) are the main excitatory and inhibitory neurotransmitters in the CNS, respectively. We studied glutamate and GABA concentrations in the PCC/precuneus via magnetic resonance spectroscopy (MRS) at 7T in relation to age and correlated them with functional connectivity between this region and other DMN nodes in ten healthy right-handed volunteers ranging in age between 23-68 years. Mean functional connectivity of the PCC/precuneus to the other DMN nodes and the glutamate/GABA ratio significantly correlated with age (r = 0.802, p = 0.005 and r = 0.793, p = 0.006, respectively) but not with each other. Glutamate and GABA alone did not significantly correlate with age nor with functional connectivity within the DMN. The glutamate/GABA ratio and functional connectivity of the PCC/precuneus are, therefore, independent age-related biomarkers of the DMN and may be combined in a multimodal pipeline to study DMN alterations in various disease states.
静息态脑默认模式网络（DMN）是大脑的主要大规模网络，后扣带回/楔前叶是该网络的主要枢纽。谷氨酸和 GABA（γ-氨基丁酸）分别是中枢神经系统中的主要兴奋性和抑制性神经递质。我们通过在 7T 磁共振波谱（MRS）中研究了 10 名健康右利手志愿者中后扣带回/楔前叶的谷氨酸和 GABA 浓度，这些志愿者的年龄在 23-68 岁之间。该区域与其他 DMN 节点之间的功能连接与谷氨酸/GABA 比值与年龄显著相关（r = 0.802，p = 0.005 和 r = 0.793，p = 0.006），但彼此之间没有相关性。谷氨酸和 GABA 单独与年龄或 DMN 内的功能连接均无显著相关性。因此，后扣带回/楔前叶的谷氨酸/GABA 比值和功能连接是 DMN 的独立年龄相关生物标志物，可能会结合在一个多模态管道中，以研究各种疾病状态下 DMN 的改变。
