Researcher receives grant to study how exposure to social stress impacts the brain and behavior

Dr. Kim Huhman, a researcher in the Center for Behavioral Neuroscience (CBN) at Georgia State University, has received a federal five-year, $1.8 million grant for research that may lead to improved strategies for treating and preventing mental health problems associated with exposure to social stress.

The grant from the National Institute of Mental Health will aid Huhman's study of how exposure to social stress causes changes in brain and behavior. Most humans experience social stress as the result of exposure to bullying, abuse or conflict in school, home and the workplace.

"These social stressors have been shown to cause or contribute to a wide variety of illnesses, including heart disease, depression and anxiety disorders," said Huhman, who, in addition to her role as a CBN researcher, is a professor in Georgia State's Neuroscience Institute and Department of Psychology. "The current treatment strategies for stress-related illnesses such as depression and anxiety disorders are inadequate for a significant number of patients. We hope to improve these outcomes significantly."

To study how social stress leads to changes in the brain and behavior, Huhman developed an animal model of social stress in hamsters. After being defeated even a single time by a larger, more aggressive opponent, hamsters exhibit pronounced social avoidance even when interacting with much smaller, non-aggressive individuals. The Huhman lab calls this pronounced change in behavior "conditioned defeat."

Conditioned defeat occurs even though hamsters are not injured during the initial defeat. The social stress is relatively mild and mainly psychological. Defeated hamsters (as well as rats and mice) also show anxiety- and depression-like changes in behavior such as alterations in feeding, sleep and startle responses, and decreases in interest in previously preferred stimuli. By studying how social stress causes conditioned defeat, Huhman aims to improve understanding of how, from a neurobiological standpoint, psychological stress has deleterious effects on physical and psychological health.

Conditioned defeat offers a unique opportunity to explore how multiple brain circuits that mediate fear/anxiety, emotional learning, social behavior and motivation interact to control complex social behavior and to "shift" or "switch" individuals among stable behavioral states. The nature of such switches and how they can have such a dramatic impact on future behavior is a fundamental unanswered question in behavioral neuroscience.

According to Huhman, "because these brain circuits are largely the same in rodents and humans, the data generated by this project will have important implications for the potential therapeutic usefulness of drugs, currently in the testing phase, to alter behavioral responses to social stress".