When it comes to treating eating disorders and tackling obesity, scientists know the brain holds the keys to unlocking answers to the most intriguing questions. Now, with help from a new grant, a Florida State University researcher is studying occurrences in specific regions of the brain that motivate us to reach for food and the impact these processes have on eating habits and weight gain.

Xiaobing Zhang, an assistant professor with the FSU Program in Neuroscience and the Department of Psychology, has received a five-year, $1.8 million grant from the National Institute of Diabetes and Digestive and Kidney Diseases, part of the National Institutes of Health, to study how certain neural circuits in the brain regulate eating behaviors. Zhang was awarded the grant for his project, “Serotonin signaling in zona incerta and paraventricular thalamus regulate feeding behavior.”

The project focuses on identifying novel serotonin pathways in the regulation of feeding and other motivated behaviors. Serotonin, a neurotransmitter produced by specific neurons in the raphe nucleus of the brainstem, exerts critical functional regulations in emotion, motivation, and behaviors due to their projections broadly to many brain areas in the cortex, limbic system, thalamus and hypothalamus. Zhang and his team plan to deconstruct the functional neural connections from raphe serotonin neurons to the zona incerta, in the subthalamus region, and the paraventricular thalamus region of the brain.

“We are very excited about this award from NIH to support our research to further study neural signaling that regulate food intake by targeting zona incerta and paraventricular thalamus, two brain areas with inhibitory neural connections for feeding control revealed by our previous findings,” Zhang said. “We hope to understand how and when these pathways are activated for feeding control. More importantly, we hope to reveal how these pathways are altered by a chronic high-fat diet that leads to overeating and obesity.”

Obesity has become a global health threat due to the increased risk of obesity-related complications, including heart disease, diabetes and end-stage renal disease. In the United States, the age-adjusted prevalence of obesity in adults increased to more than 40 percent in 2018, according to the Centers for Disease Control and Prevention. Experts warn that the high prevalence of obese and overweight individuals is largely attributable to the widespread overconsumption of easily available, energy-dense foods high in fat and sugar.

Zhang is confident this project will help scientists tackle obesity through developing a clearer understanding of what is occurring within serotonin systems in the brain that impact different eating behaviors, particularly when neurological systems are not functioning as expected.

“According to previous studies, we know food intake is tightly controlled by the brain based on its ability to sense the metabolic signals of the body and initiate motivated food consumption. However, it remains largely unknown how neuroplasticity and brain dysfunction are involved in the development of obesity and eating disorders due to complex neural pathways for the brain to integrate emotional, reward, and satiety signals,” Zhang said. “The funded work is important for not only understanding central serotonin signaling in feeding control, but also revealing a potential involvement of serotonin dysfunction in the development of obesity and overeating.”

“Studies of eating behavior and energy balance represent a historical strength at FSU,” said Frank Johnson, psychology department chair. “It is exciting to see Xiaobing build on this tradition, taking his research and our mission of student training in important new directions.”

Lisa Eckel, director of the FSU Program in Neuroscience, said Zhang’s new NIH grant will utilize electrophysiological techniques to record the electrical activity of neurons and optogenetic techniques to control neuron activity using light to better understand the serotonergic circuits that control food intake, and how changes in the activity of these circuits can influence the motivation to consume palatable food and promote weight gain.

“This project highlights some of the important, translational research being conducted by members of the neuroscience program,” Eckel said. “This innovative work is expected to reveal how dysfunctional serotonin signaling promotes overeating and unhealthy weight gain, with the long-term goal of identifying novel pharmacological targets for treating eating disorders and obesity.”