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PATIENT CARE, RESEARCH, AND EDUCATION FROM Spring 2010 THE WOODRUFF HEALTH SCIENCES CENTER

Why do fall in love? And what that means for health. 2 FEATURE LISTENING TO THE CouplingBy Sylvia Wrobel

Monogamy— style

What does love—or at least —have to do with autism, schizophrenia, and other conditions with deficits in socialcial awarenessawareness and attachment? Larry Young (left) believes his quirky little prairie voles hold some answers. Once mating is over, fidelity does not come naturally to the vast majority of species.. Even within species whose members do engage in social bonding, like , some individuals are better at it than others. The popular question was, “Why do voles fall In the 1990s, Young (William P. Timmie in love?” The answer, said the scientists, was that created lifelong attachment. Professor of Psychiatry at Emory and chief of behavioral neuroscience at Yerkes National Primate Research Center) and Tom Insel (then director of Yerkes and now director of the National Institute of Mental Health) created a scientific and media storm when they reported that the surprisingly ubiquitous and long-lasting monogamy exhibited by a species of voles is attributable to hormones. The popular ques- tion was, “Why do voles fall in love?” The answer, said the scientists, was that oxytocin—the same released during labor, delivery, and breast feeding in humans and that promotes mother-infant bonding— creates the female ’s lifelong attachment to her male partner. A related hormone, , causes the male prairie vole to cling to the female with whom he has just had sex, forsaking all others as long as they both shall live.

Spring 2010 3 FEATURE LISTENING TO THE HORMONES

In , the produc- gene for vasopressin can predict whether a tion of these hormones person will be generous, altruistic—even, occurs in response to according to a Swedish study, more likely to events like birth or marry or report satisfaction with relation- sex. But remember the ships. What role might these genetic varia- beauteous queen in tions play in human disorders—and what A Midsummer Night’s could be done to compensate for them? Dream, who becomes For example, the best treatment now besmitten with the clod- available for autism is behavioral therapy dish, donkey-headed focused on social stimulation. Could oxyto- Bottom the Weaver cin help people with autism be more recep- after she consumes a tive to social interaction? Psychosis symp- love potion designed to toms in schizophrenia can be treated, but make her fall for the first patients often are left with social deficits, for creature she sees? When which there is no current treatment. Could Young gives a female prai- oxytocin activate the social part of the brain But the story is not so romantic for all rie vole a dose of oxytocin or a male a dose of in these people? voles. Unlike the highly social, monogamous, vasopressin, the bonds on sight with Young recently took two major steps to and shared-parenting prairie voles, meadow the nearest potential mate, even before mat- garner more information from his hamster- voles couldn’t care less about past sexual ing occurs. sized . First, he and a colleague con- partners or, for that matter, pretty much any Young believes similar processes are vinced the NIH to sequence the vole genome other animal in the colony. Meadow voles going on in the human brain, which also within the next two years, a move that will are solitary and promiscuous. Males are contains oxytocin and vasopressin receptors. accelerate the discovery of genes contribut- uninvolved and seemingly unaware of their Previous studies conducted at other institu- ing to social function. offspring. tions have shown that sniffing oxytocin (pills Second, the Yerkes collaborators devel- In a finding that could have interesting would not make it past the blood-brain bar- oped the first transgenic voles, a technology implications for humans, Young next discov- rier) causes the human brain to pay more that allows them to manipulate individual ered that the chief difference between the attention to the fine details of social signals. genes to understand their effect on social two species centers on the number and loca- Eye contact increases. Individuals become bonding and other complex social behaviors. tion of neuroreceptors that select, bind, and better at deciphering emotions from facial Eventually, he believes the model could be respond to oxytocin and vasopressin. While both species of voles have these receptors, the One predictable response to this research was the sudden availability prairie voles’ receptors are concentrated in of pricey oxytocin sprays for dating, business meetings, or other situ- the brain’s pleasure regions, the same regions involved in addiction. Young believes that ations in which a little instant bonding might come in handy. activation of these receptors during mating leads to a kind of addiction to the partner. expressions and body movements, more used to improve social cognition. A male , on the other hand, likely to remember faces as being familiar, The next step will be to apply the discov- is more likely to respond to vasopressin even more likely to trust. eries made in voles to non-human primates, with territorial behavior. Unless, that is, a One predictable response to this research whose brain function is more similar to that vasopressin receptor gene is inserted into was the sudden availability of pricey oxy- of humans. Young already is working with the pleasure region of the brain. This single tocin sprays designed for dating, business other Yerkes investigators to examine the role change converts the promiscuous meadow meetings, or other situations in which a of oxytocin and vasopressin in non-human vole into an animal capable of forming strong little instant bonding might come in handy. primate social behavior. social bonds, beginning with the female Someday, maybe, shrugs Young. What com- placed in his cage. Conversely, blocking the pels him, he says, is what these discoveries vasopressin receptor in a prairie vole’s brain may say about autism, schizophrenia, and WEB CONNECTION To see a video on vole is sufficient to prevent such attachments. other disorders characterized by deficits in bonding, visit whsc.emory.edu/home/multi- Hormonally and behaviorally, the once faith- social engagement. media/videos/social-bonding-voles.html. ful prairie vole is turned into a cad. We know, he says, that variations in the

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