title: Prospective coding of dorsal raphe reward signals by the orbitofrontal cortex.
abstract: The orbitofrontal cortex (OFC) is important for the cognitive processes of learning and decision making. Previous recordings have revealed that OFC neurons encode predictions of reward outcomes. The OFC is interconnected with the dorsal raphe nucleus (DRN), which is a major serotonin (5-HT) center of the brain. Recent studies have provided increasing evidence that the DRN encodes reward signals. However, it remains unclear how the activity of DRN neurons affects the prospective reward coding of OFC neurons. By combining single-unit recordings from the OFC and optogenetic activation of the DRN in behaving mice, we found that DRN stimulation is sufficient to organize and modulate the anticipatory responses of OFC neurons. During pavlovian conditioning tasks for mice, odorant cues were associated with the delayed delivery of natural rewards of sucrose solution or DRN stimulation. After training, OFC neurons exhibited prospective responses to the sucrose solution. More importantly, the coupling of an odorant with delayed DRN stimulation resulted in tonic excitation or inhibition of OFC neurons during the delay period. The intensity of the prospective responses was affected by the frequency and duration of DRN stimulation. Additionally, DRN stimulation bidirectionally modulated the prospective responses to natural rewards. These experiments indicate that signals from the DRN are incorporated into the brain reward system to shape the cortical prospective coding of rewards.
authors: School of Life Sciences, Peking University, Beijing 100081, People's Republic of China, National Institute of Biological Sciences, Beijing 102206, People's Republic of China, and.
authors: Jingfeng
authors: J
authors: Zhou
authors: National Institute of Biological Sciences, Beijing 102206, People's Republic of China, and.
authors: Chunying
authors: C
authors: Jia
authors: National Institute of Biological Sciences, Beijing 102206, People's Republic of China, and.
authors: Qiru
authors: Q
authors: Feng
authors: National Institute of Biological Sciences, Beijing 102206, People's Republic of China, and.
authors: Junhong
authors: J
authors: Bao
authors: National Institute of Biological Sciences, Beijing 102206, People's Republic of China, and School of Life Sciences, Tsinghua University, Beijing 100084, People's Republic of China luomm@mail.tsinghua.edu.cn.
authors: Minmin
authors: http://orcid.org/0000-0003-3535-6624
authors: M
authors: Luo
mesh_terms: D000818:Animals; D001522:Behavior, Animal / Q000502:physiology; D003214:Conditioning, Classical / Q000502:physiology; D004193:Discrimination Learning / Q000502:physiology; D005260:Female; D005625:Frontal Lobe / Q000502:physiology*; D008297:Male; D051379:Mice; D009474:Neurons / Q000502:physiology; D062308:Optogenetics; D011903:Raphe Nuclei / Q000502:physiology*; D012201:Reward; D012903:Smell / Q000502:physiology
keywords: dorsal raphe nucleus; multichannel recording; optogenetics; orbitofrontal cortex; pavlovian conditioning