In the blog Head Kick Legend (part of the SB Nation) author David Castillo broke down what concussions mean to fans of combat sports. However it goes beyond sports like MMA and boxing, it paints a great picture for the reader as to what is going on; not only in the brain at a axonal level, but throughout sports.
It is a very extensive read, but worth your time if you are struggling to figure out what is happening at the cellular level;
So what exactly happens to the brain when it’s rattled? In a mild concussion, a split second hurricane of neural events occurs in which too much calcium impairs the mitochondria cells (the power centers), and leaves the brain lacking in the ability to sufficiently restore glucose in the brain. The younger you are, the more susceptible you are to long term damage. And this damage manifests itself with many different symptoms: dizziness, sensitivity to light, mood disorders, vomiting, confusion, slurred speech, and fatigue. But to dig even deeper on exactly what is being done to the brain upon trauma, experiments with axons have been highlighted off the work of Douglas Smith at the University of Pennsylvania.
Smith builds miniature brains out of rat neurons, which are then ‘hit’ with controlled puffs of air to simulate brain trauma at a molecular level. The axon is like a paperboy, sending neurological news, referred to as neurotransmitters, to “homes” called dendrites. The findings show that as axons stretch upon trauma, like a worn rubber band, they lose their elasticity after swelling, where proteins then block the proper neural absorption until the axons fall apart (called Diffuse Axonal Injury). Axons are considered vulnerable even “months after an initial stretch”, according to Smith, emphasizing the fragile nature of the brain in general, and the fragile nature of the axon, specifically.
This “traffic jam” of hoarded proteins, caused by the sudden acceleration/deceleration of the head, destroys axonal connections, which are important for the function of neurotransmitters that often do wonderful things. They inform sociability (seratonin), optimism, and persistence (dopamine), and even, as love expert and anthropologist, Helen Fisher has argued, the characteristics that model our capacity for romantic love, such as excessive energy, sleeplessness, loss of appetite, and the type of acute memory for new stimuli that allows us to keep from perceiving time spent with an intimate partner as trivial (associated with norepinephrine). Is this why athletes with a history of concussions are statistically more likely to suffer from clinical depression (20% in males with a history of concussions as opposed to merely 6% in your average male)? Are they being deprived of the chemical cocktail that helps sketch the foundation of our many different emotions, and instincts? The idea that “you are your brain” is an absurdly reductionist concept, but that’s not to say it’s not without a percentage of truth.
Castillo continues on with passages about; CTE and the accumulation of hits to the head including “subconcussive” traumas, the frontal lobe of the brain, the general criticism, and the future. Other than the usage of “mild concussion” in the opening salvo, it is a good piece to look over and think about.