Neural mechanisms of reward processing and emotion

眼眶额叶皮质(OFC)和内侧额叶皮质(MFC)中的神经元都编码了预期和收到奖励结果的感觉特性、大小和主观价值。此外，这些区域的神经元活动反映了预期唤醒，这是由瞳孔直径衡量的。 决策和唤醒的表现是紧密相连的。这些过程如何在单个神经元和神经回路水平上相互作用尚不清楚。为了了解OFC和MFC如何影响觉醒和决策，我们记录了动物做出奖励引导决策时这两个区域的神经活动。心率(HR)被记录为唤醒的代用品。在完整的动物中，我们发现较高的心率促进了反应时间(RTS)。同时，OFC和MFC中的一组神经元选择性地编码与奖励大小无关的心率的逐次尝试变化。杏仁核损毁后，HR普遍增加，HR与RTS的关系颠倒。在这种变化的同时，编码HR的MFC神经元的比例增加。在群体水平上，MFC的编码平衡向HR信号转移，这表明唤醒通过一种特定的机制来影响决策。

Neurons in both the orbitofrontal cortex (OFC) and medial frontal cortex (MFC) encode the sensory properties, magnitude and subjective value of expected and received rewarding outcomes. In addition, the activity of neurons in these regions reflects anticipatory arousal, as measured by pupil diameter. Decision-making and representations of arousal are intimately linked. How these processes interact at the level of single neurons as well as neural circuits are unknown. To understand how OFC and MFC influence arousal and decision making, we recorded neural activity from both regions while animals made reward-guided decisions. Heart rate (HR) was recorded as a proxy for arousal. In intact animals we found that higher HR facilitated reaction times (RTs). Concurrently, a set of neurons in OFC and MFC selectively encoded trial-by-trial variations in HR independent of reward magnitude. After amygdala lesions, HR generally increased and the relationship between HR and RTs was reversed. Concurrent with this change, there was an increase in the proportion of MFC neurons encoding HR. At the population level, the balance of encoding in MFC shifted towards signaling HR, suggesting a specific mechanism through which arousal influences decision-making.