Working memory (WM) is one of the fundamental cognitive functions associated with the dorsolateral prefrontal cortex (DLPFC). However, the neurochemical mechanisms of WM, including the dynamic changes in neurometabolites such as glutamate and GABA in the DLPFC, remain unclear. Here, we investigated WM-related glutamate and GABA changes, alongside hemodynamic responses in the DLPFC, using a combination of functional magnetic resonance spectroscopy (fMRS) and functional magnetic resonance imaging (fMRI). During a WM task, we measured Glx (glutamate + glutamine) and GABA levels using GABA editing MEscher-GArwood Point REsolved Spectroscopy (MEGA-PRESS) sequence and blood-oxygen-level-dependent (BOLD) signal changes. In the DLPFC, we observed elevated Glx levels and increased BOLD signal changes during a 2-back task. Specifically, the Glx levels in the DLPFC were significantly higher during the 2-back task compared with fixation, although this difference was not significant when compared with a 0-back task. However, Glx levels during the 0-back task were higher than during fixation. Furthermore, there was a positive correlation between Glx levels in the DLPFC during the 2-back task and the corresponding BOLD signal changes. Notably, higher Glx increases were associated with increased DLPFC activation and lower WM task performance in individuals. No notable changes in DLPFC GABA levels were observed during WM processing. These findings suggest that the modulation of glutamatergic activity in the DLPFC may play a crucial role in both working memory processing and its associated performance outcomes.

中文翻译：

---

工作记忆过程中背外侧前额叶皮层动态神经化学变化的初步研究

工作记忆（WM）是与背外侧前额叶皮层（DLPFC）相关的基本认知功能之一。然而，WM 的神经化学机制，包括 DLPFC 中谷氨酸和 GABA 等神经代谢物的动态变化，仍不清楚。在这里，我们结合使用功能磁共振波谱 (fMRS) 和功能磁共振成像 (fMRI)，研究了与 WM 相关的谷氨酸和 GABA 变化，以及 DLPFC 中的血流动力学响应。在 WM 任务中，我们使用 GABA 编辑 MEscher-GArwood 点分辨光谱 (MEGA-PRESS) 序列和血氧水平依赖性 (BOLD) 信号变化测量了 Glx（谷氨酸 + 谷氨酰胺）和 GABA 水平。在 DLPFC 中，我们在 2-back 任务期间观察到 Glx 水平升高和 BOLD 信号变化增加。具体来说，与固定任务相比，2 回任务期间 DLPFC 中的 Glx 水平显着更高，尽管与 0 回任务相比，这种差异并不显着。然而，0-back 任务期间的 Glx 水平高于注视期间。此外，在 2-back 任务期间 DLPFC 中的 Glx 水平与相应的 BOLD 信号变化之间存在正相关。值得注意的是，较高的 Glx 增加与个体 DLPFC 激活增加和 WM 任务表现降低相关。在 WM 处理过程中，未观察到 DLPFC GABA 水平发生显着变化。这些发现表明，DLPFC 中谷氨酸能活性的调节可能在工作记忆处理及其相关的表现结果中发挥至关重要的作用。