Wise Young
11-17-2006, 12:00 AM
Love me, only me, and forever. There must be a fairy tale somewhere that has a man or woman wishing for some potion that does this to their loved one. Perhaps such a potion drunk at the time of marriage would reduce the rates of divorce that now roil families around the world.
http://web.sfn.org/index.cfm?pagename=brainBriefings_loveAndTheBrain
Some of the new research finds that our ability to love and bond to others arises from the activation of certain brain circuits that are thought to help reinforce behaviors by producing feelings of pleasure or reward. For example, in one recent study, researchers used imaging techniques to highlight the brain activity of people experiencing romantic love or maternal love. Participants in the romantic group professed to be "truly, deeply, and madly in love" with a boyfriend or girlfriend. Researchers measured the groups' brain activity while they viewed pictures of their boyfriend or girlfriend, compared with pictures of friends. In the maternal group, moms viewed pictures of their infants, compared with pictures of other babies they were acquainted with. The study found that regions in the brain's reward system were active in participants experiencing romantic love or maternal love. In addition, the areas coincide with some regions where the brain hormones oxytocin and vasopressin are active.
A series of studies in mice-like animals, known as prairie voles, which have a penchant for monogamy, indicate that both of these hormones are important for social attachment. For example, researchers found that supplements of either oxytocin or vasopressin increase the voles' social contact with other voles and their development of a preference for a familiar partner. When voles receive a compound that blocks the activity of either oxytocin or vasopressin, supplements of the hormones do not create any partner preference and social contact is low. This and other work in voles shows the hormones aid attachment.
Although it's still not clear how the findings translate to humans, some research indicates that these hormone systems may malfunction in people who have difficulties with social interaction. Included are those with autism who also tend to have problems communicating and often repeat activities again and again. One study discovered that a group of children with autism had lower levels of oxytocin in their blood than a group of normal children, suggesting that their oxytocin systems were failing. Other work also found preliminary evidence that those with autism may harbor deficits in their vasopressin systems.
Based on these findings, researchers are interested in designing methods that could normalize the hormone systems in people with autism. They recently found that infusions of oxytocin reduced repetitive behaviors in adults with autism while they were receiving the hormone.
Next, scientists plan to test whether the hormone supplements aid social deficits in people with autism. The infusion technique, however, doesn't create lasting effects, so scientists also plan to develop other strategies that may better stabilize the oxytocin system.
<more>
So, what does one have to do... take the love potion every day in order to remain faithful? Given the notorious forgetfulness of people, this won't work. So, perhaps one should implant a slow-release system? Well, people will forget to refill the system. How about gene therapy? It seems that it may work:
The Monogamy Gene? An Animal Study
By increasing expression of the arginine vasopressin receptor gene, researchers made promiscuous meadow voles act like prairie voles, their monogamous relatives.
Genetic influences on complex mammalian behaviors have become the subject of much research. For example, species with differing expression and brain distribution of the arginine vasopressin receptor gene (V1aR) show different affiliative and caregiving patterns. These researchers investigated the relation of V1aR to affiliative behavior in meadow voles, which are promiscuous and express this gene differently from monogamous prairie voles.
Researchers increased V1aR expression in male meadow voles by injecting a viral vector for the gene into their ventral pallidum. Controls were meadow voles given either a non-V1aR vehicle or the V1aR viral vector outside the ventral pallidum. Researchers then measured the time that voles spent huddling with a partner or a stranger and reaching out to their pups. The behavioral studies were repeated after the animals were treated with the dopamine antagonist eticlopride; D2-receptor antagonists are known to block bonding with a partner in voles, but dopamine distribution tends not to vary between vole species, unlike the marked variation of V1aR.
Autoradiographs confirmed V1aR overexpression in the ventral pallidum of voles injected with the gene compared with V1aR expression in controls. Compared with controls, voles with overexpressed V1aR showed significantly greater huddling with a single partner than with strangers and greater paternal caring. When voles with overexpressed V1aR were treated with eticlopride, bonding, but not paternal caring, significantly decreased.
Comment: In this study, manipulation of a single gene, V1aR, made promiscuous meadow voles behave like monogamous prairie voles. Further, dopamine blockade decreased the affiliative behavior, but not the paternal caring, which demonstrates the dissociation of the two pathways. How these animal behaviors relate to human bonding will be important to investigate.
— Barbara Geller, MD
Wise.
http://web.sfn.org/index.cfm?pagename=brainBriefings_loveAndTheBrain
Some of the new research finds that our ability to love and bond to others arises from the activation of certain brain circuits that are thought to help reinforce behaviors by producing feelings of pleasure or reward. For example, in one recent study, researchers used imaging techniques to highlight the brain activity of people experiencing romantic love or maternal love. Participants in the romantic group professed to be "truly, deeply, and madly in love" with a boyfriend or girlfriend. Researchers measured the groups' brain activity while they viewed pictures of their boyfriend or girlfriend, compared with pictures of friends. In the maternal group, moms viewed pictures of their infants, compared with pictures of other babies they were acquainted with. The study found that regions in the brain's reward system were active in participants experiencing romantic love or maternal love. In addition, the areas coincide with some regions where the brain hormones oxytocin and vasopressin are active.
A series of studies in mice-like animals, known as prairie voles, which have a penchant for monogamy, indicate that both of these hormones are important for social attachment. For example, researchers found that supplements of either oxytocin or vasopressin increase the voles' social contact with other voles and their development of a preference for a familiar partner. When voles receive a compound that blocks the activity of either oxytocin or vasopressin, supplements of the hormones do not create any partner preference and social contact is low. This and other work in voles shows the hormones aid attachment.
Although it's still not clear how the findings translate to humans, some research indicates that these hormone systems may malfunction in people who have difficulties with social interaction. Included are those with autism who also tend to have problems communicating and often repeat activities again and again. One study discovered that a group of children with autism had lower levels of oxytocin in their blood than a group of normal children, suggesting that their oxytocin systems were failing. Other work also found preliminary evidence that those with autism may harbor deficits in their vasopressin systems.
Based on these findings, researchers are interested in designing methods that could normalize the hormone systems in people with autism. They recently found that infusions of oxytocin reduced repetitive behaviors in adults with autism while they were receiving the hormone.
Next, scientists plan to test whether the hormone supplements aid social deficits in people with autism. The infusion technique, however, doesn't create lasting effects, so scientists also plan to develop other strategies that may better stabilize the oxytocin system.
<more>
So, what does one have to do... take the love potion every day in order to remain faithful? Given the notorious forgetfulness of people, this won't work. So, perhaps one should implant a slow-release system? Well, people will forget to refill the system. How about gene therapy? It seems that it may work:
The Monogamy Gene? An Animal Study
By increasing expression of the arginine vasopressin receptor gene, researchers made promiscuous meadow voles act like prairie voles, their monogamous relatives.
Genetic influences on complex mammalian behaviors have become the subject of much research. For example, species with differing expression and brain distribution of the arginine vasopressin receptor gene (V1aR) show different affiliative and caregiving patterns. These researchers investigated the relation of V1aR to affiliative behavior in meadow voles, which are promiscuous and express this gene differently from monogamous prairie voles.
Researchers increased V1aR expression in male meadow voles by injecting a viral vector for the gene into their ventral pallidum. Controls were meadow voles given either a non-V1aR vehicle or the V1aR viral vector outside the ventral pallidum. Researchers then measured the time that voles spent huddling with a partner or a stranger and reaching out to their pups. The behavioral studies were repeated after the animals were treated with the dopamine antagonist eticlopride; D2-receptor antagonists are known to block bonding with a partner in voles, but dopamine distribution tends not to vary between vole species, unlike the marked variation of V1aR.
Autoradiographs confirmed V1aR overexpression in the ventral pallidum of voles injected with the gene compared with V1aR expression in controls. Compared with controls, voles with overexpressed V1aR showed significantly greater huddling with a single partner than with strangers and greater paternal caring. When voles with overexpressed V1aR were treated with eticlopride, bonding, but not paternal caring, significantly decreased.
Comment: In this study, manipulation of a single gene, V1aR, made promiscuous meadow voles behave like monogamous prairie voles. Further, dopamine blockade decreased the affiliative behavior, but not the paternal caring, which demonstrates the dissociation of the two pathways. How these animal behaviors relate to human bonding will be important to investigate.
— Barbara Geller, MD
Wise.