Key connection in neural code of 'love' uncovered in vole study

New research probes the neural circuitry responsible for pair bonding in prairie voles.

From Woodruff Health Sciences

A team of neuroscientists from Emory University's Silvio O. Conte Center for Oxytocin and Social Cognition has discovered a key connection between areas of the adult female prairie vole's brain reward system that promotes the emergence of pair bonds. Results from this study, published this week in Nature, could help efforts to improve social abilities in human disorders with impaired social function, such as autism.

This Conte Center study is the first to find the strength of communication between parts of a corticostriatal circuit in the brain predicts how quickly each female prairie vole becomes affiliative with her partner; prairie voles are socially monogamous and form lifelong bonds with their partners. Additionally, when researchers boosted the communication by using light pulses, the females increased their affiliation toward males, thus further demonstrating the importance of this circuit's activity to pair bonding in prairie voles.

"Prairie voles were critical to our team's findings because studying pair bonding in humans has been traditionally difficult," says co-lead author Elizabeth Amadei. "As humans, we know the feelings we get when we view images of our romantic partners, but, until now, we haven't known how the brain's reward system works to lead to those feelings and to the voles' pair bonding."

Building upon previous work in prairie voles that demonstrated brain chemicals, such as oxytocin and dopamine, act within the medial prefrontal cortex and nucleus accumbens to establish a pair bond, the team set out to address finding the precise neural activity leading to a pair bond. The researchers used probes to listen to neural communication between these two brain regions and then analyzed activity from individual female prairie voles as they spent hours socializing with a male - a cohabitation period that normally leads to a pair bond.

The team discovered that during pair bond formation, the prefrontal cortex, an area involved in decision-making, helps control the rhythmic oscillations of neurons within the nucleus accumbens, the central hub of the brain's reward system. This suggests a functional connection from the cortex shapes neurons activity in the nucleus accumbens.

The team then noticed individual voles varied in the strength of this functional connectivity. Importantly, each subject with stronger connectivity showed more rapid affiliative behavior with her partner, measured as side-by-side huddling contact. Furthermore, the pair's first mating, a behavior that accelerates bonding in voles, strengthened this functional connection, and the amount of strengthening correlated with how quickly the animals subsequently huddled.

"It is remarkable there are neural signatures of a predisposition to begin huddling with the partner. Similar variation in corticostriatal communication could underlie individual differences in social competencies in psychiatric disorders in humans, and enhancing that communication could improve social function in disorders such as autism," says Larry Young, co-author and director of the Conte Center and chief of the Division of Behavioral Neuroscience and Psychiatric Disorders at Yerkes National Primate Research Center.

The study results led the team to ask more questions, including whether communication between the prefrontal cortex and nucleus accumbens not only correlates with huddling but also causally facilitates it. To answer this, the researchers used optogenetics, a technique that allowed them to enhance communication between the brain areas using light, and enhanced communication between the prefrontal cortex and nucleus accumbens of female voles during a brief cohabitation without mating, which is not conducive to pair bonding.

The team discovered optogenetically stimulated animals showed greater preference toward partners compared to a stranger male when given a choice the following day.

"It is amazing to think we could influence social bonding by stimulating this brain circuit with a remotely controlled light implanted into the brain," says Zack Johnson, co-lead author. The study results identify an important reward circuit in the brain that is activated during social interactions to facilitate bond formation in voles.

"Now, we want to know if oxytocin regulates functional connectivity and how circuit activity changes the way the brain processes social information about a partner," says senior author Robert Liu, associate professor in Emory's Department of Biology. "Our team's work is an example of a larger effort in neuroscience to better quantify how brain circuits function during natural social behaviors. Our goal is to promote better neural communication to boost social cognition in disorders such as autism, in which social functioning can be impaired," Liu adds.

Amadei and Johnson were both graduate students who attained their PhD's this year. Additional Emory-based co-authors are graduate students Yong Jun Kwon and Varun Saravanan, undergraduate student Aaron Shpiner, and Wittney Mays, Steven Ryan, PhD, Hasse Walum, PhD, and Donald Rainnie, PhD.

The goal of the Silvio O. Conte Center for Oxytocin and Social Cognition is to improve human health by leading coordinated and rigorous research programs to discover the neural mechanisms by which oxytocin modulates social cognition. The research represents a unique collaboration among Emory University's Emory College of Arts and Sciences, School of Medicine and Yerkes National Primate Research Center, and the Wallace H. Coulter Department of Biomedical Engineering at Georgia Institute of Technology and Emory University.

Georgia Climate Project creates state 'climate research roadmap'

Environmental sciences instructor Daniel Rochberg, chief strategy officer for Climate@Emory, says the Georgia Climate Research Roadmap aims to create "Georgia's Top 40," a set of targeted research questions to help the state understand and address climate change. (Emory Photo/Video)

By Kimber Williams
Emory Report

Scientists, researchers and environmental experts from across the state convened at Emory last week to draft the “Georgia Climate Research Roadmap” — a set of targeted research questions that could help Georgia better understand and address one of the century’s defining challenges.

The goal of the May 22-23 gathering was to formulate “Georgia’s Top 40,” key climate research questions that could eventually aid decision-making and planning for Georgia policymakers, scientists, communities and service organizations.

An initiative of the Georgia Climate Project, the roadmap was a response to the fact that communities across Georgia are already exploring strategies to address the impact of climate change, says Daniel Rochberg, chief strategy officer for the Climate@Emory initiative and an instructor in the Rollins School of Public Health and Emory College of Arts and Sciences, where he focuses on climate change and sustainable development.

Some Georgia communities are actively assessing vulnerabilities and strategies to build resilience to potential climate change impact, while others are developing technologies and policies to begin reducing emissions, according to Rochberg, who has also worked for the U.S. State Department as special assistant to the lead U.S. climate negotiators under presidents Bush and Obama.

“To inform this work, decision-makers at all levels need credible and relevant information from across the natural, applied and social sciences,” says Murray Rudd, an associate professor in Emory’s Department of Environmental Sciences and member of the climate research roadmap steering committee. “The Georgia Climate Research Roadmap seeks to fulfill this need by identifying the key research questions that, if answered, can lay the groundwork for the state and its residents to take effective, science-based climate action,” he says.

Read the full story in Emory Report.

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Dads show gender biases, in both brain responses and behaviors, toward toddlers

“Our study provides one of the richest datasets for fathers now available,” says Emory neuroscientist Jennifer Mascaro. (Stock image) 

By Carol Clark

A toddler’s gender influences the brain responses as well as the behavior of fathers — from how attentive they are to their child, to the types of language that they use and the play that they engage in, a new study by Emory University finds.

The journal Behavioral Neuroscience published the study, the first to combine brain scans of fathers with behavioral data collected as fathers interacted with their children in a real-world setting.

One of the more striking behavioral differences was the level of attention given a child.

“When a child cried out or asked for Dad, fathers of daughters responded to that more than did fathers of sons,” says Jennifer Mascaro, who led the research as a post-doctoral fellow in the lab of Emory anthropologist James Rilling, senior author of the study. “We should be aware of how unconscious notions of gender can play into the way we treat even very young children.”

Mascaro is now an assistant professor in Family and Preventive Medicine at the Emory School of Medicine.

In addition to being more attentive, fathers of daughters sang more often to their child and were more likely to use words associated with sad emotions, such as “cry,” “tears” and “lonely.” Fathers of daughters also used more words associated with the body, such as “belly,” “cheek,” “face,” “fat” and “feet.”

Fathers of sons engaged in more rough-and-tumble play with their child and used more language related to power and achievement — words such as “best,” “win,” “super” and “top.” In contrast, fathers of daughters used more analytical language — words such as “all,” “below” and “much” — which has been linked to future academic success. 

“It’s important to note,” Rilling says, “that gender-biased paternal behavior need not imply ill intentions on the part of fathers. These biases may be unconscious, or may actually reflect deliberate and altruistically motivated efforts to shape children’s behavior in line with social expectations of adult gender roles that fathers feel may benefit their children.”

The study showed that fathers of sons engaged in more rough-and-tumble play with their child, a finding consistent with previous research by others. (Stock image)

Most parental studies draw from data gathered in a lab, where parents answer questions about their behavior and where they may be observed briefly as they interact with their children. This study collected behavioral data in a real-world setting through an electronic activated recorder (EAR), which was developed in the lab of co-author Matthias Mehl at the University of Arizona.

The participants included 52 fathers of toddlers (30 girls and 22 boys) in the Atlanta area who agreed to clip a small personal digital assistant equipped with the EAR software onto their belts and wear it for one weekday and one weekend day. The fathers were also told to leave the device charging in their child’s room at night so any nighttime interactions with their children could be recorded. The device randomly turned on for 50 seconds every nine minutes to record any ambient sound during the 48-hour period.

“People act shockingly normal when they are wearing the device,” Mascaro says. “They kind of forget they are wearing it or they say to themselves, what are the odds it’s on right now. The EAR technology is a naturalistic observation method that helped us verify things about parental behavior that we suspected based on previous research. It also uncovered subtle biases that we didn’t necessarily hypothesize in advance.”

In addition, fathers underwent functional MRI brain scans while viewing photos of an unknown adult, an unknown child and their own child with happy, sad or neutral facial expressions. Fathers of daughters had stronger responses to their daughters’ happy expressions in areas of the brain important for processing emotions, reward and value. In contrast, the brains of fathers of sons responded more robustly to their child’s neutral facial expressions.

“Most parents really are trying to do the best they can for their children,” Mascaro says. “A take-home point is that it’s good to pay attention to how your interactions with your sons and daughters may be biased." (Stock image)

The study focused on fathers because there is less research about their roles in rearing young children than mothers. “Our study provides one of the richest datasets for fathers now available, because it combines real-world assessments of behavior with brain responses,” Mascaro says. “It appears that men’s brain responses to their children may be related to their behaving differently with sons compared to daughters.”

The findings are consistent with other studies indicating that parents — both fathers and mothers — use more emotion language with girls and engage in more rough-and-tumble play with boys. It is unclear whether these differences are due to biological and evolutionary underpinnings, cultural understandings of the way one should act, or some combination of the two.

“We also don’t know the long-term child outcomes,” Mascaro says. “But future research can test the hypothesis that these differences have demonstrable impacts on things like empathy, emotional regulation and social competence.”

The use of more emotion language with girls by fathers, for example, may help girls develop more empathy than boys. “The fact that fathers may actually be less attentive to the emotional needs of boys, perhaps despite their best intentions, is important to recognize,” Mascaro says. “Validating emotions is good for everyone — not just daughters.”

Restricted emotions in adult men is linked to depression, decreased social intimacy, marital dissatisfaction and a lower likelihood of seeking mental health treatment.

Research also shows that many adolescent girls have negative body images. “We found that fathers are using more language about the body with girls than with boys, and the differences appear with children who are just one-to-three years old,” Mascaro says.

And while they use more words about the body with girls, fathers engage in more physical rough-and-tumble play with boys, an activity that research has shown is important to help young children develop social acuity and emotional regulation.

“Most parents really are trying to do the best they can for their children,” Mascaro says. “A take-home point is that it’s good to pay attention to how your interactions with your sons and daughters may be biased. We need to do more research to try to understand if these subtle differences may have important effects in the long term.”

The American Psychological Association contributed to this story.

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Climate change is in Atlanta's air

"We're all partly responsible for our local air quality," says Emory graduating senior Emily Li. "Even if we don't hold ourselves accountable, our health will." (Emory Photo/Video)

By Carol Clark

Emory 2017 graduate Emily Li is leaving Atlanta this summer, but her student research will continue to have a presence here. For her undergraduate thesis, Li investigated the effects of shifting weather patterns on the air quality of Atlanta and the region — and how that relates to human health. She’s compiled her findings into a web site, Climate Change is in the Air, as a resource for local residents. 

“The web site explains some of the science involved, but it’s not just statistics,” Li says. “It also tells stories of real people. I wanted to put faces on these complex, scientific processes and explain how individuals are being directly affected by climate change, right now.”

In addition to science and stories from real people, the site offers solutions — what communities and individuals can do to address the issue.

Li, who majored in Environmental Sciences and English, sampled classes from a range of disciplines during college. No matter what the course, however, climate change kept coming up. “I think that it’s the most important issue that we face today, and I want to be part of the solution,” she says.

As a junior, Li took a course called Environmental Journalism, taught by Sheila Tefft, and realized that she could combine her two passions: Science and communication.

The web site focuses on how climate change is connected to Atlanta’s air quality, and how air quality is connected to the health of everyone living here. “Everybody has to breathe the air,” Li says. “We each need about 50 pounds of air a day and we can only go without it for about five minutes. Air is what we use the most and need the most to survive.”

The air pollutants that are contributing to a warming climate also contribute to problems of human health across the body — from the functions of lung and bronchial airways to cardiovascular diseases and central nervous system disorders. For the web site, Li concentrated on the respiratory health impacts of aeroallergens, wildfire emissions and ground-level ozone.

In lush Atlanta, a city famous for its “pollen explosions,” a warming climate may mean a longer exposure to pollen from many plants. Li tells the story of a fellow Emory student with a range of plant allergies to show the impact that high pollen counts can have on an individual’s life. “It’s hard to enjoy a nice spring day when you have to take a nap afterwards just for breathing the air,” she writes.

Hot, dry conditions also contribute to wildfires in Georgia, including an ongoing blaze in the Okefenokee National Wildlife Refuge. Hundreds of firefighters are currently battling the fire as it threatens to spread beyond the swamp to nearby communities.

To personalize the impact of the wildfire emissions, Li interviewed a firefighter from north Georgia. She described his experience of a minor smoke inhalation episode: “The condition is first initiated by a deep-set exhaustion: He’s already usually hot, sweaty and tired out from the firefighting work. Overwhelmed, his respiratory system begins to let down its defenses. Then he starts to get a tightness in his chest, like his upper body is being squeezed by an invisible fist. It becomes hard for him to fully catch his breath, and he can feel a distinct obstruction in his windpipe with every attempt to suck air into his lungs. At the same time, his energy levels plummet dangerously.”

The firefighter explained to Li: “With wildfire, typically there’s a lot of walking that has to happen and a lot of strenuous activity getting to remote areas. It’s just not possible or feasible to carry air packs or self-contained breathing apparatus into the wilderness or remote areas and sustain that air supply.”

The topic of ground-level ozone is also covered on the web site, although the personal story for that section remains under construction.

Li is leaving Atlanta to pursue a masters degree in education from the University of Pennsylvania, but she plans to keep adding to the site — and perhaps expand it to encompass other cities across the country.

“My goal is to create an immersive experience that people can not just learn from, but connect to,” Li says. “I want to bridge the emotional distance between people and the science of climate change.” 

The solutions offered on the site are a critical part of that goal, she adds. “One of my main suggestions is to just stay informed and aware and spread that awareness any way that you can,” Li says. “The more people that understand the problem, the better.”

Atlanta residents also have a chance to make a difference as the Atlanta Regional Commission works on a Regional Transportation Plan aimed at meeting Clean Air Act requirements. “Anyone can join the conversation to help make the plan a reality,” Li says.

Researching the potential impacts of climate change was overwhelming at times but ultimately rewarding, Li says. “Working on this project has made me much more deliberate in my actions. It’s also made me aware of not only how I can contribute to solutions to climate change, but how I can help other people stay hopeful and helpful so they can take action as well.”

Related:
How will the shifting political winds affect U.S. climate policy?

A Reddit Science Q&A on medical ethnobotany

What does a medical ethnobotanist have growing in her home garden? Is it possible to patent the berry of a plant? What's the difference between a natural and a synthetic product?

Emory ethnobotanist Cassandra Quave answered these questions and many more during her popular Reddit Science Ask-Me-Anything (AMA) session last Friday. The lively session sparked more than 400 comments within a few hours. Quave, assisted by members of her lab, answered most of the questions posed to her. "I've enjoyed the opportunity to discuss our research with so many interested people," Quave told the Reddit community.

Click here to read her archived Reddit AMA.

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