The Surprising Role of Oxytocin: It’s Not Just about Love, But Friendship Too
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Oxytocin, often dubbed the “love hormone,” plays a far more complex role in social bonding than previously understood.New research from the University of California, Berkeley, reveals that oxytocin isn’t solely responsible for romantic attachment; it’s also crucial for forming and maintaining friendships, and even for navigating social boundaries. The study, published in Current Biology, sheds light on how a lack of oxytocin signaling impacts both close relationships and interactions with strangers, offering insights into the neurobiology of social selectivity.
For years,oxytocin has been linked to pair bonding,especially in prairie voles,which are known for their monogamous relationships. However,this new research demonstrates that oxytocin is equally important for establishing and maintaining peer relationships - the bonds we share with friends.
Researchers discovered that prairie voles lacking oxytocin receptors showed delays in forming relationships with both mates and peers. Interestingly, these voles exhibited a heightened motivation to reunite with a mating partner, even more so than voles with functioning oxytocin receptors. This suggests that the reward pathways associated with romantic relationships are particularly reliant on oxytocin signaling.”They press more to get to their mating partner, but not for peer relationships,” explains Dr. Aubrey Beery, a postdoctoral researcher at UC Berkeley and co-author of the study. “That makes sense at some level because we think mate relationships are more rewarding than peer relationships,or at least they depend more on reward-signaling pathways.”
However, the absence of oxytocin wasn’t just about difficulty forming bonds. It also impacted the quality of existing relationships. Voles without oxytocin receptors experienced deficits in long-term peer relationships, highlighting the hormone’s ongoing role in maintaining social connections.
The study also revealed a surprising side to oxytocin’s influence: it plays a role in social rejection.Voles lacking oxytocin receptors were less aggressive towards, and less avoidant of, unfamiliar voles. This suggests that oxytocin isn’t simply about seeking connection; it’s also about establishing boundaries and recognizing who is “in” and who is “out” of one’s social group.
“You can see contributions of oxytocin signaling to both sides of selectivity,” says beery. “On the prosocial side,it’s involved in wanting to be with a known friend or peer,while on the antisocial side,it’s aiding in rejecting an unfamiliar animal. We’ve seen effects of oxytocin on both affiliation and aggression in our other studies in prairie voles, and it parallels human findings on a role of oxytocin in in-group/out-group dynamics.”
This duality underscores the nuanced role of oxytocin in social behavior, demonstrating its importance in navigating the complexities of social life.
Unraveling the Mechanism: Oxytocin Release in the Brain
To understand how a lack of oxytocin receptors affects social behavior, the researchers needed to determine whether the absence of receptors led to changes in oxytocin release. It was possible that the brain attempted to compensate by producing more oxytocin, which could then bind to alternative receptors.To investigate this, the team utilized innovative oxytocin nanosensors developed in Dr. Landry’s UC Berkeley lab. These sensors, constructed from carbon nanotubes and DNA, fluoresce when they bind to oxytocin molecules, allowing researchers to visualize oxytocin release in real-time.
the results were unexpected. Rather of finding increased oxytocin levels, the researchers discovered that voles lacking oxytocin receptors actually released less oxytocin from fewer sites in the nucleus accumbens – a brain region critical for social reward across species.
“This suggests that the lack of receptors isn’t being compensated for by increased release,” explains Dr. Landry, an associate professor at UC Berkeley and co-corresponding author of the paper. “The system is fundamentally disrupted.”
This finding provides crucial insight into the mechanisms underlying oxytocin’s role in social bonding, suggesting that the hormone’s effects are dependent on the presence of functional receptors.
This research has meaningful implications for understanding social behavior in both animals and humans. By pinpointing the specific role of oxytocin in both affiliation and rejection, the study offers a more complete picture of the neurobiology of social selectivity.
Further research could explore whether similar mechanisms are at play in humans, potentially leading to new therapeutic strategies for individuals struggling with social deficits
