On January 16, 2016 the University of Pennsylvania announced the findings of a unique team studying concussion science, consisting of a professor of materials science and engineering and a professor of neurosurgery (also director of Penn Center for Brain Injury and Repair.)

The team has developed a new mathematical model of how permanent injury can happen on the molecular scale. The model evaluates why axons, the connections that allow brain cells to communicate with each other, can be damaged by a sudden force, even though they are understood to be quite elastic. The researchers note that “microtubules” run down the length of the axons in bundles, linked by a protein known as “tau.”  The link between the tau proteins and the microtubules is, however, not permanent – the proteins bind and unbind every few seconds, allowing the microtubules to slide relative to one another without damage and enabling the axon to stretch up to twice its original length. A rapid jolt –a concussive force – does not allow this process to take place. “When you pull [the microtubules] very fast, that bond doesn’t break and the forces get exerted on the microtubule itself. That’s what’s causing the damage in a traumatic brain injury.”

As the researchers note, an interesting aspect of this model is that it shows the tau protein as the center of axon damage in concussion. Aggregation of tau protein is the signature of chronic traumatic encephalopathy, (CTE) the neurodegenerative condition found in some athletes with multiple head traumas. Dr. Omalu, the pathologist played by Will Smith in the new movie “Concussion”,  discovered pathological tau protein deposits throughout the brain of Mike Webster and other players who developed symptoms of neurodegeneration following their football careers.