Tau is a type of protein that naturally exists in the brain. Under normal conditions, tau proteins help stabilize microtubules which are tiny structures inside nerve cells (neurons) that act like “tracks” for transporting nutrients and signals. You can think of them as the scaffolding that keeps brain cells structured and functional. However, when the brain experiences repeated trauma from punches, strikes, or sudden jolts these nerve cells become stressed or damaged. This damage causes tau proteins to misfold (change shape) and clump together, forming what scientists call “tau tangles” or neurofibrillary tangles. Over time, these abnormal tau proteins spread throughout the brain, disrupting communication between neurons and eventually causing cells to die. This process leads to atrophy (brain shrinkage) and loss of function in areas responsible for thinking, memory, emotions, and movement.