Few people see much in common between candy and cocaine, aside from their identical first letter. Not so for Matt Will, Assistant Professor of Psychology at the University of Missouri-Columbia. Will’s current research links our cravings for fatty, high calorie foods with serious drug abuse. He examines the neurochemistry that controls the intake of these types of substances, and “gives us the craving for foods such as ice cream.” Through their experiments, Will and his team of graduate and undergraduate students have found that the chemistry driving food intake is comparable to the chemistry driving drug addiction.
Experiments in the Behavioral Neuroscience Lab are conducted with rat models. The researchers surgically implant tubes into the rat brain and then “use a map of the brain to target specific regions that we know are involved in drug addiction and all the feeding processes.” After implanting the tubes, the researchers inject different drugs into the designated regions, including opioids, feel-good chemicals that cause rats to binge eat. Next, says Will, “we look at other brain regions and how they cooperate with the opioids to allow this binge eating to occur.”
As he explains, the reason behind such binge eating isn’t increasing hunger—rather, “it is increasing the palatability of the food.” When people eat high-fat foods, opioids are released in the brain, and “these feel-good chemicals make the food taste better, just like ice cream tastes better than broccoli to most people.” This is no recent development in our neurochemistry. According to Will, humans “were programmed through evolution to seek out foods that are high in energy.” Tens of thousands of years ago, food was less plentiful and people endured periods of famine and food shortage in which eating high quantities of calories in one sitting made sense—thus, modern-day people are genetically coded to do the same, drawn to the high-fat, high-sugar foods that cause obesity. In this way, we humans are “fighting our own biology.”
So how can we combat our biology and overcome obesity when our neurochemistry actually programs us to eat unhealthily? Will hopes that his research will serve as “groundwork to think beyond,” so that a pharmacologist could design drugs to counteract or lessen the effects of opioids on our appetites. Though he admits “the research is a bit far from developing the drug,” he is optimistic about the future as he conducts these experiments. He hopes that his research will make people realize that they “need more willpower”—although our brains are programmed to seek out high-caloric foods, we need to control ourselves and counteract these built-in, evolutionary eating habits.
In addition to his primary study of food and drug abuse, Will is also collaborating with a colleague in the Department of Biomedical Sciences to study the connections between exercise and addiction. Toward this end, Will and Dr. Frank Booth study the “runner’s high” in rats. Like drugs or fatty foods, Will explains, “running is one of these things that produces natural rewarding chemicals in the brain. By measuring the distances and looking at how runners' diets change, they can analyze differences in the brain and “parallels between what we expect in an addicted brain compared to the non-addicted brain.”
Interestingly, because addiction to exercise produces the same neurochemical effect as addiction to “high-fat palatable food” or drugs, Will says that exercise can serve as a treatment plan for drug as well as food addictions. “They all fall under this umbrella of rewarding events,” he notes. “All rewarding events have the potential to deregulate your system, and you can become addicted to them,” whether they involve gambling, eating fatty, high-caloric food, or even exercising. “If you have someone who is a drug addict, or someone who is overeating because of an addiction—then if you can introduce another natural reinforcer, such as exercise, you might be able to reduce the addiction level to the substance that you are trying to wean him off of. That’s how it all theoretically fits together.”
Will's other collaborative connections include a study on autism and food intake conducted with neurologist Dr. David Beversdorf and graduate student Karen Jones. Together they investigate how the diets of mice, along with their exposure to stress, affected the later onset of autism in their children. As he explains, exploring the mother's eating habits is important because “the diet may be a type of trigger that could affect the development of the fetus.” Examining the interaction between stress and diet is imperative as well: there is correlational evidence that human mothers who “are exposed to stress in areas of the world that have the type of diet that we’ve been giving these mice do have a higher incidence of autism.” Using controlled conditions in the lab, Will and Beversdorf measure the autism-like symptoms the mice demonstrate, including deficits in sociability, communication, and learning. Will hopes that this research will help expectant human mothers so that high-risk pregnant mothers could lessen the chances of autism in their children by altering their gestational diet to diminish the influence of high-stress situations.
Notably, much of Will’s research has resulted from his cross-disciplinary, collaborative approach. Trained as a behaviorist looking at how to model certain behaviors in rats, Will is often approached by other researchers who want to analyze behavior in their models. More than just a consultant, Will says that breaking out of his niche and interacting with faculty in different departments has enhanced his own work: “by doing this other project that was at first unrelated, you find out that it actually does give you more inspiration for your own project and helps your original focus.”
Aside from cross-disciplinary collaboration, Will notes that teaching provides additional inspiration for his research. When presenting his findings to students—“fresh minds that have no preconceived ideas”—Will gets questions he hasn’t thought of because he is “so deep into it.” Likewise, he finds that incorporating his research into teaching is a seamless process. Will teaches an undergraduate course in physiological psychology and a graduate course in functional neuroscience. “We end up studying sensory systems like taste, and then homeostatic systems such as feeding,” he explains. “My research falls right into that, so I always try to give them a little window into the field, of what it’s like to be a researcher. I provide them with what I think is more of the cutting-edge science than what they would get from the textbook.” Many of Will’s students eventually approach him about opportunities in the lab, so he has a team of undergraduates and graduates alike who pursue independent honors projects or help him conduct experiments related to grant proposals. No matter the project, the students get trained in surgery and behavioral analysis, which is a “very critical experience” for those considering graduate school.
In addition to contributions from undergraduate and graduate students, Will’s laboratory has received crucial support in the form of a University of Missouri Research Board Grant. The Research Board funded Will’s study of neural substrates of feeding. Thanks to this timely support, he was able to purchase state-of-the-art equipment that allows automated analysis of feeding. This equipment was beneficial to the lab because the automation insures that “you don’t have to be in the room disturbing the rats to measure their behavior,” making data collection more efficient and accurate. The equipment gave Will “new information that I wouldn’t have gotten otherwise, and it really took part of our research project in another direction.”
In addition, the grant allowed him to conduct related research, with graduate students Kyle Parker and Jordan McCall, on how certain feel-good chemicals (opioids and cannabinoids, the chemicals in the brain mimicked by marijuana) react to different types of foods. Will explains that by studying how the chemicals act in “synergistic fashion to different types of food, we can better understand how food and drugs of abuse act on the brain similarly.” Though opioids are “the main culprit” behind binge eating, cannabinoids function similarly—both “work to increase appetite driven by the increase of palatability.” The chemicals also “work together in the brain to produce this euphoric feeling you get after eating high fat or palatable diets.” Will hopes to see this research lead to the development of a drug to block the negative effects of both opioids and cannabinoids, in order to decrease appetite and problems associated with addiction.
Funding from the Research Board has also helped Will win external funding from the National Institutes of Health to study a neural mechanism involved in high-fat feeding. “The pilot data I acquired from the UMRB grant was definitely critical in getting the external funding,” he observes. This research has already resulted in several publications on the interaction of opioids and cannabinoids.
From appetite and addiction to autism and exercise, Will’s research reaches many different audiences. If his many initiatives come to fruition, they could help diminish the prevalence of obesity, drug abuse, and neurodevelopmental disorders. As it turns out, there is much more in common between candy and cocaine than one might expect.