Discounting larger, delayed rewards for smaller, immediate rewards is a stable psychological trait known to be impaired in gambling disorder (GD). Neuroimaging with non-GD populations indicates involvement of anterior cingulate (ACC) and dorsolateral prefrontal cortex (dlPFC) in delay discounting. However, little is known about the role of intrinsic properties of brain functioning, such as neurotransmitter action, in impaired discounting in GD. Here, we used magnetic resonance spectroscopy to assess glutamate-glutamine (Glx) and γ-amino-butyric acid (GABA+) concentrations in the dorsal ACC (dACC), dlPFC and occipital cortex of human males with and without GD. Gambling symptom severity correlated negatively with Glx levels in the dACC and occipital voxels. Discounting of small and medium delayed rewards was negatively associated with GABA+ in the dACC, while the discounting of large delayed rewards was negatively associated with GABA+/Glx ratios in the dlPFC. Additionally, in GD, discounting of large delayed rewards was negatively correlated with occipital GABA+ levels. Overall, these findings show that high gambling symptom severity is associated with low levels of Glx and that dACC (GABA+), right dlPFC (GABA+/Glx), and occipital areas (GABA+) track the magnitude of delayed rewards during discounting.

中文翻译：

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冲动决策和赌博严重性：γ-氨基-丁酸 (GABA) 和谷氨酸-谷氨酰胺 (Glx) 的影响

将较大的、延迟的奖励打折以获得较小的即时奖励是一种稳定的心理特征，已知在赌博障碍 (GD) 中受到损害。非 GD 人群的神经影像学表明前扣带回 (ACC) 和背外侧前额叶皮层 (dlPFC) 参与延迟折扣。然而，关于大脑功能的内在特性（例如神经递质作用）在 GD 折现受损中的作用知之甚少。在这里，我们使用磁共振波谱来评估有和没有 GD 的人类男性背侧 ACC (dACC)、dlPFC 和枕叶皮层中谷氨酸-谷氨酰胺 (Glx) 和 γ-氨基-丁酸 (GABA+) 的浓度。赌博症状的严重程度与 dACC 和枕骨体素中的 Glx 水平呈负相关。中小延迟奖励的折扣与 dACC 中的 GABA+ 呈负相关，而大延迟奖励的折扣与 dlPFC 中的 GABA+/Glx 比率呈负相关。此外，在 GD 中，大延迟奖励的折扣与枕骨 GABA+ 水平呈负相关。总体而言，这些发现表明，高赌博症状严重程度与 Glx 水平低有关，dACC (GABA+)、右 dlPFC (GABA+/Glx) 和枕区 (GABA+) 跟踪折扣期间延迟奖励的程度。