Zhixiang Liu, Jingfeng Zhou, Yi Li, Fei Hu, Yao Lu, Ming Ma, Qiru Feng, Ju-en Zhang, Daqing Wang, Jiawei Zeng, Junhong Bao, Ji-Young Kim, Zhou-Feng Chen, Salah El Mestikawy, Minmin Luo
Neuron, Volume 81, Issue 6, 1360-1374, 19 March 2014
中脳背側縫線核（midbrain dorsal raphe nucleus）に存在するセロトニン・ニューロンは報酬に反応する。
The dorsal raphe nucleus (DRN) in the midbrain is a key center for serotonin (5-hydroxytryptamine; 5-HT)-expressing neurons. Serotonergic neurons in the DRN have been theorized to encode punishment by opposing the reward signaling of dopamine neurons. Here, we show that DRN neurons encode reward, but not punishment, through 5-HT and glutamate. Optogenetic stimulation of DRN Pet-1 neurons reinforces mice to explore the stimulation-coupled spatial region, shifts sucrose preference, drives optical self-stimulation, and directs sensory discrimination learning. DRN Pet-1 neurons increase their firing activity during reward tasks, and this activation can be used to rapidly change neuronal activity patterns in the cortex. Although DRN Pet-1 neurons are often associated with 5-HT, they also release glutamate, and both neurotransmitters contribute to reward signaling. These experiments demonstrate the ability of DRN neurons to organize reward behaviors and might provide insights into the underlying mechanisms of learning facilitation and anhedonia treatment.