Longitudinal Changes of Quantitative Brain Tissue Properties Induced by Balance Training

The human brain can show remarkable experience-induced plasticity under conditions such as aging and pathology. However, the mapping of changes provided by many imaging approaches often lacks specificity with respect to biological tissue properties, which is relevant for treatment optimization and the evaluation of health-promoting lifestyle factors. Training-induced structural changes in cortical and subcortical gray matter likely reflect a mixture of various microstructural processes. In order to non-invasively map these different microstructural contributions, we used quantitative magnetic resonance imaging (qMRI) to measure clinically-relevant brain tissue property changes (such as iron, myelin, and water) in response to 4 weeks of motor balance training in 26 healthy young adults. Training resulted in a regionally-specific decrease in myelin-related magnetization transfer saturation (MT_sat) in the left frontal cortex. We also found performance-related changes in iron-sensitive transverse relaxation rate (R2*) in visual cortical (signal increase along with positive performance correlation) and limbic subcortical (signal decrease along with negative performance correlation) brain areas. Our study contributes to a growing body of literature investigating motor training-induced microstructural brain plasticity. Specifically, we provide new insights into microstructural brain changes using whole-body motor learning (balance practice) and longitudinal quantitative mapping of brain tissue properties.