Structural brain changes with learning and recovery from stroke.

Learning to juggle can physically rewire the white matter pathways in an adult human brain—and this project will use that finding to understand how the brain repairs itself after a stroke. Most studies of brain plasticity have focused on grey matter, the tissue where neurons cluster. But the researchers recently discovered that learning also changes the microstructure of white matter, the brain’s long-distance communication cables. The problem is that current brain scans can detect these changes but cannot explain what is happening at the cellular level. Without that understanding, doctors cannot design therapies that reliably promote recovery after stroke or brain injury. This project has two parallel tracks. In humans, the team will track how white and grey matter change over time during learning, and whether age alters that plasticity. In rats, they will perform the same scans and then examine the brain tissue under a microscope, linking the imaging signals to specific cellular events—such as myelin wrapping or axon sprouting. If successful, the work will give clinicians a biological target for stroke rehabilitation: a measurable, cell-level change to aim for. For the wider imaging community, it will reveal what structural brain scans actually mean, turning a fuzzy signal into a precise diagnostic tool.