Tract-specific white matter microstructure and gait in humans.

Gait is a complex sequence of movements, requiring cooperation of many brain areas, such as the motor cortex, somatosensory cortex, and cerebellum. However, it is unclear which connecting white matter tracts are essential for communication across brain areas to facilitate proper gait. Using diffusion tensor imaging, we investigated associations of microstructural organization in 14 brain white matter tracts with gait, among 2330 dementia- and stroke-free community-dwelling individuals. Gait was assessed by electronic walkway and summarized into Global Gait, and 7 gait domains. Higher white matter microstructure associated with higher Global Gait, Phases, Variability, Pace, and Turning. Microstructure in thalamic radiations, followed by association tracts and the forceps major, associated most strongly with gait. Hence, in community-dwelling individuals, higher white matter microstructure associated with better gait, including larger strides, more single support, less stride-to-stride variability, and less turning steps. Our findings suggest that intact thalamocortical communication, cortex-to-cortex communication, and interhemispheric visuospatial integration are most essential in human gait.