Sexual dimorphism in striatal dopaminergic responses promotes monogamy in social songbirds
Abstract
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.
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Author details
Funding
National Science Foundation (1261872)
- Kirill Tokarev
- Ofer Tchernichovski
National Science Foundation (956306)
- Henning U Voss
National Science Foundation (1065678)
- Santosh A Helekar
National Institutes of Health (DC04722-17)
- Kirill Tokarev
- Ofer Tchernichovski
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Ethics
Animal experimentation: This study was conducted in accordance with the guidelines of the US National Institutes of Health and was approved by the Institutional Animal Care and Use Committees of Hunter College of the City University of New York (protocol 'OT imaging 10/18-01') and Weill Cornell Medical College (protocol #2010-0003).
Copyright
© 2017, Tokarev et al.
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.
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