The source of Intellectual activity-Neural basis of Default activity

两只猴子在WM（空间延迟交替）任务中训练。我们研究了猴子在（1）执行WM任务时的多巴胺释放（WM任务期）和（2）安静地坐着，没有任务表现和没有奖励（REST期）。在WM任务期间，我们观察到一个显着减少多巴胺的释放相比，在休息期间在内侧前额叶皮层（PFC）。神经影像学研究表明背外侧PFC的激活与WM任务表现有关，背外侧PFC中多巴胺释放的增加被认为在WM任务表现中起重要作用。相反，在内侧PFC，我们观察到增加的rCBF和多巴胺释放在休息期间相比，WM任务期间。我们的研究结果表明，认知操作与默认模式的大脑活动在内侧PFC可能会支持增加多巴胺的释放。

Two monkeys were trained in a WM (spatial delayed alternation) task. We examined dopamine release while the monkey was (1) performing the WM task with a liquid reward (WM task period) and (2) sitting quietly without task performance and without reward (REST period). During the WM task period, we observed a significant decrease in dopamine release compared with during the REST period in the medial prefrontal cortex (PFC). Neuroimaging studies have indicated activations of the dorsolateral PFC in relation to WM task performance, and increased dopamine release in the dorsolateral PFC is considered to play essential roles in WM task performance. In contrast, in the medial PFC, we observed increases in both the rCBF and dopamine release during REST as compared with WM task period. Our results suggest that cognitive operations associated with default-mode brain activity in the medial PFC may be supported by the increased dopamine release.