Biomedical Magnetic Resonance, Otto-von-Guericke University, 39120 Magdeburg, Germany.
J Neurosci. 2013 Jul 31;33(31):12698-704. doi: 10.1523/JNEUROSCI.1758-13.2013.
Magnetic resonance spectroscopy (MRS) of glutamatergic or GABAergic measures in anterior cingulate cortex (ACC) was found altered in psychiatric disorders and predictive of interindividual variations of functional responses in healthy populations. Several ACC subregions have been parcellated into receptor-architectonically different portions with heterogeneous fingerprints for excitatory and inhibitory receptors. Similarly, these subregions overlap with functionally distinct regions showing opposed signal changes toward stimulation or resting conditions. We therefore investigated whether receptor-architectonical and functional segregation of the cingulate cortex in humans was also reflected in its local concentrations of glutamate (Glu), glutamine (Gln), and GABA. To accomplish a multiregion estimation of all three metabolites in one robust and reliable session, we used an optimized 7T-stimulated echo-acquisition mode method with variable-rate selective excitation pulses. Our results demonstrated that, ensuring high data retest reliability, four cingulate subregions discerning e.g., pregenual ACC (pgACC) from anterior mid-cingulate cortex showed different metabolite concentrations and ratios reflective of regionally specific inhibition/excitation balance. These findings could be controlled for potential influences of local gray matter variations or MRS voxel-placement deviations. Pregenual ACC was found to have significantly higher GABA and Glu concentrations than other regions. This pattern was not paralleled by Gln concentrations, which for both absolute and relative values showed a rostrocaudal gradient with highest values in pgACC. Increased excitatory Glu and inhibitory GABA in pgACC were shown to follow a regional segregation agreeing with recently shown receptor-architectonic GABAB receptor distribution in ACC, whereas Gln distribution followed a pattern of AMPA receptors.
磁共振波谱（MRS）对前扣带皮层（ACC）谷氨酸能或 GABA 能的测量发现，在精神疾病中发生改变，并可预测健康人群中功能反应的个体间变化。已经将几个 ACC 亚区划分为具有不同受体结构的不同部分，具有兴奋性和抑制性受体的异质指纹。同样，这些亚区与功能不同的区域重叠，表现出对刺激或静息条件的相反信号变化。因此，我们研究了人类扣带皮层的受体结构和功能分离是否也反映在其局部谷氨酸（Glu）、谷氨酰胺（Gln）和 GABA 浓度上。为了在一次稳健可靠的会议中对所有三种代谢物进行多区域估计，我们使用了优化的 7T 激发回波采集模式方法，带有可变速率选择性激发脉冲。我们的结果表明，确保高数据复测可靠性，四个扣带皮层亚区可辨别例如，前扣带皮质（pgACC）与前中扣带皮质，显示出不同的代谢物浓度和比值，反映了区域特异性的抑制/兴奋平衡。这些发现可以控制局部灰质变化或 MRS 体素放置偏差的潜在影响。发现前扣带皮质（pgACC）的 GABA 和 Glu 浓度明显高于其他区域。这种模式与 Gln 浓度不一致，无论是绝对值还是相对值，都表现出 pgACC 中最高的额尾梯度。pgACC 中增加的兴奋性 Glu 和抑制性 GABA 被证明与最近在 ACC 中显示的受体结构 GABAB 受体分布一致，而 Gln 分布遵循 AMPA 受体的模式。
