Evolutionarily conserved role of oxytocin in zebrafish social reward encoding.
Kareklas. Kyriacos K; Herrera-Castillo. Lisbeth L; Levkowitz. Gil G; Oliveira. Rui F RF
Key Findings
- Wild‑type zebrafish develop a place preference for a neutral cue paired with a sibling, indicating a social reward.
- Zebrafish lacking the oxytocin receptor (oxtr mutants) fail to show this preference, proving the receptor is necessary for social reward encoding.
- The effect occurs after a brief exposure, suggesting oxytocin is involved in the initial encoding of social reward rather than later memory consolidation.
Practical Outcomes
- For biohackers, this study mainly adds basic science knowledge: oxytocin influences social motivation in fish and likely across species. It does not provide dosage guidance, protocols, or direct human applications, so its immediate utility for longevity or performance optimization is minimal.
Summary
In zebrafish, the hormone oxytocin (through its receptor) is needed for the fish to feel a social reward when it meets a sibling. Fish that lack the oxytocin receptor don't develop a preference for a place linked to that social interaction, showing oxytocin helps encode social pleasure.
Abstract
Social rewards may have evolved in social species to reinforce adaptive social interactions. Yet, evidence for social rewards is still scarce, and the underlying mechanisms remain unclear. A key candidate to regulate the value of social stimuli is oxytocin due to its role in social affiliation, which is traced to its origins in ray-finned fish-but whether it encodes rewards is uncertain. Using a single-trial conditioned place preference test, we found that wild-type zebrafish increased preference for a neutral unpreferred cue associated with a same-sex sibling, while oxytocin receptor (<i>oxtr</i>) mutants did not. These findings demonstrate the necessity of <i>oxtr</i> for social rewards, while the short exposure infers its role in encoding rather than consolidation. Our results provide evidence for an evolutionarily conserved role of oxytocin in social reward encoding given the available evidence for similar effects in rodents.
Study Information
pubmed
2025
2025-11-26T00:00:00.000Z
10.1098/rsbl.2025.0628
37