title: Reward signal in a recurrent circuit drives appetitive long-term memory formation.
abstract: Dopamine signals reward in animal brains. A single presentation of a sugar reward to Drosophila activates distinct subsets of dopamine neurons that independently induce short- and long-term olfactory memories (STM and LTM, respectively). In this study, we show that a recurrent reward circuit underlies the formation and consolidation of LTM. This feedback circuit is composed of a single class of reward-signaling dopamine neurons (PAM-α1) projecting to a restricted region of the mushroom body (MB), and a specific MB output cell type, MBON-α1, whose dendrites arborize that same MB compartment. Both MBON-α1 and PAM-α1 neurons are required during the acquisition and consolidation of appetitive LTM. MBON-α1 additionally mediates the retrieval of LTM, which is dependent on the dopamine receptor signaling in the MB α/β neurons. Our results suggest that a reward signal transforms a nascent memory trace into a stable LTM using a feedback circuit at the cost of memory specificity.
authors.affiliation: Graduate School of Life Sciences, Tohoku University, Sendai, Japan.|Max Planck Institute of Neurobiology, Martinsried, Germany.
authors.forename: Toshiharu
authors.initials: T
authors.lastname: Ichinose
authors.affiliation: Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States.
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Aso
authors.affiliation: Graduate School of Life Sciences, Tohoku University, Sendai, Japan.|Max Planck Institute of Neurobiology, Martinsried, Germany.
authors.forename: Nobuhiro
authors.initials: N
authors.lastname: Yamagata
authors.affiliation: Graduate School of Life Sciences, Tohoku University, Sendai, Japan.
authors.forename: Ayako
authors.initials: A
authors.lastname: Abe
authors.affiliation: Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States.
authors.forename: Gerald M
authors.initials: GM
authors.lastname: Rubin
authors.affiliation: Graduate School of Life Sciences, Tohoku University, Sendai, Japan.|Max Planck Institute of Neurobiology, Martinsried, Germany.
authors.forename: Hiromu
authors.initials: H
authors.lastname: Tanimoto
mesh_terms: D000818:Animals; D001070:Appetitive Behavior; D003214:Conditioning, Classical; D059290:Dopaminergic Neurons / Q000502:physiology; D004330:Drosophila / Q000502:physiology*; D057567:Memory, Long-Term; D009434:Neural Pathways; D012008:Recurrence
keywords: D. melanogaster; behavioral genetics; long-term memory; neuroscience; reward circuit