Posted April 18, 2013
Michael Platt, Ph.D., Duke University
What is the most important thing that stakeholders should know about your research?
People with Autism Spectrum Disorder (ASD) often have trouble connecting with others. Such trouble may come from differences in brain function that limit social interest, reward, and empathy. How these processes work in the healthy brain, how they break down in disorders like ASD, and how they might be rescued are open questions crucial to treating problems in social interaction. We used a new model in which monkeys have the option to share rewards with another monkey to probe these questions.
First, we showed that monkeys care about sharing rewards with other monkeys under some conditions but are remarkably selfish in others. We next explored whether intranasal oxytocin (OT), a hormone currently being evaluated as a potential treatment for social dysfunction, can make monkeys more likely to share with each other. To do this, we developed a new method to deliver OT intranasally by nebulizer, which may be more readily tolerated by children with ASD since this method is standard for delivering other treatments like asthma medicine. Next, we showed that inhaling OT makes monkeys more likely to share with other monkeys, and improves their attention to the other monkeys. Finally, we explored the neural basis of these social decisions. We found that brain cells in the anterior cingulate gyrus, which has been implicated in empathy in people, respond both to giving and receiving rewards, and do so in a very similar way. Of the three brain areas we explored, this was the only area that took into account what happened to the other monkey. This suggests the anterior cingulate gyrus is important for shared experience and social reward, and may be less functional in ASD.
What is the next step to bringing your research closer to helping individuals living with ASD now?
There are several steps we are taking. We are trying to understand how inhaling OT changes the activity of brain cells that respond to social decisions. We are specifically studying the activity of these cells while monkeys inhale OT. Additionally, we are exploring the long-term effects of inhaling OT for social function, and looking for any possible side effects. Finally, we will test these ideas while directly turning on or turning off activity in brain areas we have already found play a role in social attention and decision-making.
Is there any other information that you think readers should know about your work?
Our work is unique in that it focuses on precisely those behaviors that are impaired in people living with ASD, and focuses on the exact same brain circuits and areas. While much work on developing new therapies for ASD has focused on studies in genetically altered mice, that work, though valuable, does not address the same behaviors that both monkeys and humans engage in, such as sharing, joint attention, and the use of visual social cues to guide behavior. We are also using the monkey model to explore naturally-occurring genetic variation and its role in naturally-occurring social behavior in a semi-wild population of rhesus macaques living on an island off the coast of Puerto Rico. This study has already shown that monkeys, like humans, vary in their social abilities, with some being well-integrated into the group and others being peripheral. We also found that these traits are heritable, and are related to personality differences and genes that have been implicated in social function in people. Our te m [at Duke University] is uniquely well-positioned to address these questions because we bring a variety of different approaches to the challenge, including neuroscience, genetics, primate social behavior, fieldwork, and computational biology.