From the article:
The new research focuses on the impact that traumatic brain injury has on the glymphatic system. It has been long observed that the protein tau plays an important role in the long-term damage sustained by the brain after a trauma. Tau helps stabilize the fibers, or axons, that nerve cells send out to communicate with their neighbors.
However, during trauma, large numbers of these proteins are shaken free from the axons to drift in the space between the brain’s cells. Once unmoored from nerve cells, these sticky proteins are attracted to each other and, over time, form increasingly larger “tangles” that can become toxic to brain function.
Under normal circumstances, the glymphatic system is able to clear stray tau from the brain. However, when the researchers studied the brains of mice with traumatic brain injury, they found that the trauma damaged the glymphatic system, specifically the ability of astrocytes – a support cell found in the brain – to regulate the cleaning process.