Social Bonding: We May Be a Lot Like the Prairie Vole
May 6, 2009
In this segment, biological sciences professor Maryam Bamshad-Alavi explains how her research into these mammals can help us better understand how humans form and maintain social bonds.
9 Minutes 59 Seconds
In "Clues to the Unknown," Lehman faculty and students explain the research they are conducting—and the new knowledge and discoveries that may unfold from their work.
This is Vince Bracy, a student at Lehman College. Why are some men monogamous and paternal while others are not? The answer may lie with a small, furry rodent called a prairie vole. In this segment, biological sciences professor Maryam Bamshad-Alavi explains how her research into these mammals can help us better understand how humans form and maintain social bonds.
We know that, in our society, there are men who stay with their partner. And they're very parental. They take care of their children. But there are other men who are romantically involved with more than one woman. And still, there are men who choose not to take care of their children, that don't seem to be very parental. Now, the question is, if there is a biological reason for these differences, if these men are biologically different? Interestingly, there's a little tiny mouse that may help us find answers to these questions.
These field mice are called prairie voles. They're small mammals, rodents, that can be raised in a laboratory. And what is so interesting about prairie voles is that they behave similarly to humans. They have a social system that is similar to ours. Now, for example, in nature, we know that most male prairie voles will find a female, will mate with her, and will stay with her for life.
And once his babies are born, he is very active in parental care. He will take care of them. However, very similar to humans, there are some male prairie voles that will mate and have infants with multiple females. We are studying the factors that may influence male prairie voles to remain faithful to his mate. And help take care of his infants. We are also looking at the role of the brain in regulating these behaviors, these social behaviors.
This is based on field studies. They would tag the prairie voles. And they will always catch the same male and the female together. So they figured out that perhaps these males and females are monogamous. And they're staying together. And later on, other researchers looked at their parental behavior and found out that the male prairie voles, some of them, are very parental.
We know that the male is influenced by the female's sensory cues as the male prairie vole stays with his mate, the level of a neuropeptide called vasopressin changes in his brain. And there are other labs that have looked at the role of vasopressin in male prairie voles.
And they have shown that vasopressin appears to be involved in this formation of social bonds between a male and a female. And what I'm particularly interested in is to see where the vasopressin also plays a role in how the male responds to the female's sensory cues. And how his level of attention to infant cues may change as a result of this increased activity of vasopressin in his brain.
There are differences in the way this neuropeptide, vasopressin, is released in the brain and how it binds to its receptor. That there are differences among males who are monogamous and males who are not monogamous.
Humans also have this chemical. And there are some recent, very interesting recent research showing that vasopressin may play a role in how men who report that they are faithful and do not have as many marital problems, the level of vasopressin seems to be different from men that report that they are uncomfortable, unhappy, etc.
Actually, it is released in the blood, and it regulates blood pressure. But it's also released in the brain. And it is the release of vasopressin in the brain that affects social behavior and social communication.
My lab is interested in understanding whether the way after the male has mated with the female, and his level of vasopressin increases, does that affect the way he perceives sensory stimuli in his environment? And by receiving those sensory stimuli, how does that impact his brain so that he eventually is more motivated to care for his infant or not care for his infants?
So we know that the environment has a big influence on how these neuropeptides are released or whether they bind to receptors. And how much receptors are present in the brain. And there is a big interplay between the environment and the way these neuropeptides work.
In prairie voles, about, in males, there are 26 percent that are not monogamous. The remaining are monogamous. Or that they seem to be monogamous. Among females, 14 percent are not monogamous. The remaining appear to monogamous.
Now, if you look at humans, or recently look at a study that was done in the University of California, and they looked at the percentage of people that report having extramarital affairs.
And among men, 20, I believe 22 percent reported that they had extra marital affairs. And 14 percent of women reported to have had, admitted that they had extramarital affairs. So the percentages seem weird. I mean, it's so similar, it seems weird. These numbers could be skewed because people may not be telling the truth, not everybody might be admitting it.
And the same is true with prairie voles. When you sample prairie voles in nature, it depends on what environment you get your sample from. Or what was the population density of the prairie voles at the time when we took the sample? So the numbers could be, the percentages could be, off a little bit there, too. But they seem to be very similar.
What we are hoping to do is to simulate a condition for them that is somewhat more similar to what they might experience in the field. And see whether we can find differences in how the male chooses his mate and whether he stays with her, how much attention he gives her. So those kind of things.
Once the male and the female mate, they stay together. They form a bond. And if you give the male a choice between the female that he has mated with versus a female that is unfamiliar to him, he will mate with both of them. But he chooses to stay in contact with his mate more often than with this stranger.
They remain with the female in the nest. Once the infants are born, the male will lick the infants, which is very important for them. He will huddle with them. He will groom them. The only thing that he doesn't do that the female does is nursing. He participates in everything else. He spends a lot of time with them.
I think my research will shed light on how the brain works to form and maintain social bonds. We are hoping that this kind of research will also lead us to better understand the biology of disorders that are related to a dysfunction in social communication and bonding.
An example of that is autism. Autism has become prevalent. Or, at least, we are detecting autism in the human population. And we don't know how autism comes about. We know that it is a disorder of social communication. And which breaks down the bond that is formed between the child and the parent. But why that happens and how the brain dysfunctions to lead to autism, we don't have any answers as yet.
We did a whole study looking at the relationship, basically, between the male and his mate. And we wanted to know whether the male had to have physical contact with the female in order to show an increase in his parental care.
Or was it just being exposed to her distal cues, what we call distal cues. That is odor, sound, or looking at her. That was important to the male. And we found out that distal cues seem to increase the level of male's parental care. But he really needs to have her touch. He needs to be in contact, physical contact with her, to maximize his interest in the infants and the way he takes care of them.
I think the prairie voles have a social unit that is very similar to humans. Because the male and the female stay together, their relationship, or in case of the prairie voles, the way they communicate, these social interactions among the male and the female can influence the way both the male or the female take care of their infants.
Particularly the male seems to be more sensitive to that. Because the female gets pregnant. And we know that changes in pregnancy hormone is motivating her to take care of the infants. But the male is very sensitive to the cues that he's receiving from the female. So the interaction between the male and the female influences the way they take care of their infants.
In the same way, I think, humans, the relationship that mother and a father have together can impact the way they bond with their children. And in turn, the cues that they get from the children will help the parents form a stronger bond with their children.
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