BACKGROUND Alterations in the levels of gamma-aminobutyric acid (GABA) and glutamate + glutamine (Glx), which are major inhibitory and excitatory neurotransmitters, respectively, are frequently associated with insomnia. Previous reports also suggested the involvement of the anterior cingulate cortex (ACC) and medial prefrontal cortex (mPFC) in insomnia and shorter sleep duration. In the current study, we investigated whether the GABA and Glx levels were altered in the ACC/mPFC in subclinical insomnia while focusing on the sleep duration. METHODS We examined levels of GABA and Glx in the ACC/mPFC of the brain with magnetic resonance spectroscopy in 166 individuals with subjective sleep complaints but without a diagnosis of insomnia. Participants were divided into two groups according to sleep duration (≥6 h/night: n = 79 vs. < 6 h/night: n = 74), which was measured using a wrist-worn actigraphy. Working memory function and overall subjective sleep quality were assessed with a computerized neuropsychological test and self-report questionnaire, respectively. RESULTS GABA levels in the ACC/mPFC were lower in the shorter sleep duration group relative to the longer sleep duration group (t = -2.21, p = 0.03). Glx levels did not differ between the two groups (t = -0.20, p = 0.84). Lower GABA levels were associated with lower spatial working memory performance in the shorter sleep duration group (β = -0.21, p = 0.03), but not the longer sleep duration group (β = 0.04, p = 0.72). CONCLUSION Shorter sleep duration was associated with lower GABA levels in the ACC/mPFC. These findings may provide insight into the underlying mechanisms of impaired working memory function related to insomnia and sleep loss.

中文翻译：

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较短的睡眠时间与前扣带回皮层中较低的GABA水平相关。

背景技术分别是主要的抑制性和兴奋性神经递质的γ-氨基丁酸（GABA）和谷氨酸+谷氨酰胺（Glx）水平的改变经常与失眠有关。先前的报道还提示失眠和较短的睡眠时间涉及前扣带回皮层（ACC）和内侧前额叶皮层（mPFC）。在当前的研究中，我们研究了亚临床失眠时ACC / mPFC中GABA和Glx的水平是否改变，同时关注睡眠时间。方法我们使用磁共振波谱技术检查了166例主观睡眠不适但未诊断出失眠的人的大脑ACC / mPFC中GABA和Glx的水平。根据睡眠时间（≥6 h / night：n = 79 vs. <6 h / night：n = 74），这是使用手腕上的手印进行测量的。工作记忆功能和总体主观睡眠质量分别通过计算机化的神经心理学测试和自我报告调查表进行评估。结果相对于较长的睡眠时间组，较短的睡眠时间组的ACC / mPFC中的GABA水平较低（t = -2.21，p = 0.03）。两组之间的Glx水平无差异（t = -0.20，p = 0.84）。较短的睡眠时间组（β= -0.21，p = 0.03）中较低的GABA水平与较低的空间工作记忆表现相关，而较长的睡眠时间组（β= 0.04，p = 0.72）与较低的GABA水平相关。结论较短的睡眠时间与ACC / mPFC中较低的GABA水平有关。