Department of Psychology, Hunter College, City University of New York, New York, United States; Department of Radiology, Weill Cornell Medicine, New York, United States
Julia Hyland Bruno
Department of Psychology, Hunter College, City University of New York, New York, United States; Department of Psychology, Graduate Center of the City University of New York, New York, United States
Iva Ljubičić
Department of Psychology, Hunter College, City University of New York, New York, United States; Department of Biology, Graduate Center of the City University of New York, New York, United States
Department of Radiology, Weill Cornell Medicine, New York, United States
Santosh A Helekar
Department of Neurology, Houston Methodist Research Institute, Houston, United States
Ofer Tchernichovski
Department of Psychology, Hunter College, City University of New York, New York, United States; Department of Psychology, Graduate Center of the City University of New York, New York, United States; Department of Biology, Graduate Center of the City University of New York, New York, United States
Henning U Voss
Department of Radiology, Weill Cornell Medicine, New York, United States
In many songbird species, males sing to attract females and repel rivals. How can gregarious, non-territorial songbirds such as zebra finches, where females have access to numerous males, sustain monogamy? We found that the dopaminergic reward circuitry of zebra finches can simultaneously promote social cohesion and breeding boundaries. Surprisingly, in unmated males but not in females, striatal dopamine neurotransmission was elevated after hearing songs. Behaviorally too, unmated males but not females persistently exchanged mild punishments in return for songs. Song reinforcement diminished when dopamine receptors were blocked. In females, we observed song reinforcement exclusively to the mate’s song, although their striatal dopamine neurotransmission was only slightly elevated. These findings suggest that song-triggered dopaminergic activation serves a dual function in social songbirds: as low-threshold social reinforcement in males and as ultra-selective sexual reinforcement in females. Co-evolution of sexually dimorphic reinforcement systems can explain the coexistence of gregariousness and monogamy.
