The benefits of exercise are widely known, but few scientists have made fundamental discoveries relating exercise to brain growth and the preservation of cognition. Kirk Erickson, Ph.D., associate professor of psychology, is one of them. His research focuses on understanding the changes in various aspects of cognition, and the supporting brain structure and function, across the lifespan. He has found that participation in moderate amounts of physical activity can significantly improve cognition and brain function in older adults. In short, older brains are still “plastic,” in that age-related patterns of deterioration can be reversed through interventions such as exercise.
While he was still a graduate student, Erickson reported that fitness was associated with greater brain volume in adults age 55-79. Results of this study, the first of its kind, were published in 2003 in the Journal of Gerontology and subsequently cited more than 1000 times by other investigators. Erickson continued this line of research and, in 2011 in the Proceedings of the National Academy of Sciences, reported that supervised exercise over 12 months resulted in an increase in the size of the hippocampus, the structure of the brain needed for memory formation. The hippocampus is known to shrink in memory disorders like Alzheimer’s Disease. Erickson’s finding was considered a landmark, in that it was the first time that plasticity of this structure was shown in older adults and that a non-pharmacological treatment could change its structure.
Genetic factors, sex, and social circumstances also appear to affect brain health, according to Erickson. In one study, his team found that a genetic variation in the gene for brain derived neurotrophic factor contributes to the rate of cognitive decline in old age. BDNF assists the biological processes underpinning memory formation. His team is currently examining how genetic predispositions interact with environmental factors (e.g., physical activity) to influence neurocognitive function in old age. Erickson also is collaborating with other researchers to understand the reasons women, and especially women with breast cancer, may undergo more rapid cognitive decline than their male counterparts.
Other factors contributing to overall health also play a profound role in contributing to cognitive decline. In pilot research being conducted at the Wilkin’s Community Center center in Pittsburgh’s Edgewood neighborhood, Erickson is exploring the potential value of an exercise regimen in African Americans, who have a 4-times increased risk over Caucasians in developing dementia due to greater risk factors such as diabetes, obesity, hypertension, and lower educational levels.
Erickson has been widely commended for his work. In 2016 he was invited to participate in a U.S. Health and Human Services advisory committee to produce the 2018 edition of the Physical Activity Guidelines for Americans. In addition to his role as associate professor, Erickson holds appointments within the Center for the Neural Basis of Cognition and Center for Neuroscience. He is associated with the Claude D. Pepper Older Americans Independence Center and Alzheimer Disease Research Center. He also is the director and principal investigator of the Brain Aging and Cognitive Health Lab. His work has been honored with the Pitt Chancellor’s Distinguished Research Award, and he was named a fellow of the Academy of Behavioral Medicine as well as a University of Illinois Senior Beckman Fellow in 2014. He also is an issue specialist for the Global Council on Brain Health. Erickson earned a Ph.D. degree at the University of Illinois at Urbana-Champaign in 2005 and a bachelor’s degree in psychology and philosophy at Marquette University in 1999.
Although cognitive decline and brain atrophy is common in old age, it is far from being inevitable, according to Erickson. And while many appreciate that exercise is important to keeping a body healthy, only results of a “gold” standard phase III trial are likely to shape exercise recommendations for older adults with the goal to preserve brain health.
In late 2016, Erickson was awarded a $21.8 million award from the National Institute on Aging to study exercise and brain health in 639 cognitively normal adults age 65 to 80 years. Investigating Gains in Neurocognition in an Intervention Trial of Exercise (IGNITE) is being conducted in collaboration with Northeastern University, the University of Kansas, and the University of Illinois.
IGNITE explores four main themes:
• whether a moderate-intensity exercise intervention improves cognitive health;
• whether that intervention improves MRI-measured markers of brain health, and whether those changes are dose dependent;
• whether changes to the nervous system, heart, and metabolism mediate improvements in the brain and in cognition;
• how individual differences such as age and genetics affect the results.
This image shows results of how higher fitness levels affect white matter microstructure in older adults. Individuals that are higher fit show greater white matter microstructure in all of the colored areas. These effects were replicated across two separate samples and greater white matter microstructure mediated an association with memory function (Oberlin, LE, Verstynen, TD, Burzynska, AZ, Voss, MW, Prakash, RS, Chaddock-Heyman, L, Wong, C, Fanning, J, Awick, E, Gothe, N, Phillips, SM, Mailey, E, Ehlers, D, Olson, E, Wojcicki, T, McAuley, E, Kramer, AF, Erickson, KI. (2016). White matter microstructure mediates the relationship between cardiorespiratory fitness and spatial working memory in older adults. NeuroImage, 131: 91-101.)