The neurotransmitters GABA and glutamate have been suggested to play a role in Major Depressive Disorder (MDD) through an imbalance between cortical inhibition and excitation. This effect has been highlighted in higher brain areas, such as the prefrontal cortex, but has also been posited in basic sensory cortices. Based on this, magnetic resonance spectroscopy (MRS) was used to investigate potential changes to GABA+ and glutamate+glutamine (Glx) concentrations within the occipital cortex in MDD patients (n = 25) and healthy controls (n = 25). No difference in occipital GABA+ or Glx concentrations, nor in the GABA+/Glx ratio, was found between groups. An analysis of an extended MDD patient and unmatched control dataset (n = 90) found no correlation between metabolite concentrations and depressive symptoms. These results were integrated with prior studies through metabolite-specific meta-analyses, revealing no difference in occipital GABA and Glx concentrations between patients and controls. An effect of publication year on GABA group differences was found, suggesting that previously reported results may have been artifacts of measurement accuracy. Taken together, our results suggest that, contrary to some prior reports, MRS measurements of occipital GABA and Glx do not differ between MDD patients and controls.

中文翻译：

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重度抑郁症中枕骨γ-氨基丁酸和谷氨酸-谷氨酰胺的改变：一项mrs研究和荟萃分析

已经建议神经递质 GABA 和谷氨酸通过皮质抑制和兴奋之间的不平衡在重度抑郁症 (MDD) 中发挥作用。这种效应在较高的大脑区域（例如前额叶皮层）中得到了强调，但在基本感觉皮层中也存在。基于此，磁共振波谱 (MRS) 用于研究 MDD 患者 (n = 25) 和健康对照 (n = 25) 枕叶皮层内 GABA+ 和谷氨酸盐 + 谷氨酰胺 (Glx) 浓度的潜在变化。两组之间没有发现枕部 GABA+ 或 Glx 浓度的差异，也没有发现 GABA+/Glx 比率的差异。对扩展 MDD 患者和不匹配的对照数据集 (n = 90) 的分析发现代谢物浓度与抑郁症状之间没有相关性。这些结果通过代谢物特异性荟萃分析与先前的研究相结合，显示患者和对照组之间的枕部 GABA 和 Glx 浓度没有差异。发现出版年份对 GABA 组差异的影响，表明先前报告的结果可能是测量准确性的伪影。总之，我们的结果表明，与之前的一些报告相反，MDD 患者和对照组的枕部 GABA 和 Glx 的 MRS 测量值没有差异。