Serotonin neurons in the dorsal raphe nucleus encode reward signals

Nat Commun. 2016 Jan 28;7:10503. doi: 10.1038/ncomms10503.


The dorsal raphe nucleus (DRN) is involved in organizing reward-related behaviours; however, it remains unclear how genetically defined neurons in the DRN of a freely behaving animal respond to various natural rewards. Here we addressed this question using fibre photometry and single-unit recording from serotonin (5-HT) neurons and GABA neurons in the DRN of behaving mice. Rewards including sucrose, food, sex and social interaction rapidly activate 5-HT neurons, but aversive stimuli including quinine and footshock do not. Both expected and unexpected rewards activate 5-HT neurons. After mice learn to wait for sucrose delivery, most 5-HT neurons fire tonically during waiting and then phasically on reward acquisition. Finally, GABA neurons are activated by aversive stimuli but inhibited when mice seek rewards. Thus, DRN 5-HT neurons positively encode a wide range of reward signals during anticipatory and consummatory phases of reward responses. Moreover, GABA neurons play a complementary role in reward processing.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Dorsal Raphe Nucleus / physiology*
  • Feeding Behavior
  • Female
  • Male
  • Mice / physiology
  • Mice / psychology*
  • Neurons / physiology*
  • Reward
  • Serotonin / metabolism*


  • Serotonin