How Concussions Affect the Brain


Each year in the United States, players of sports and recreational activities receive between 2.5 and 4 million concussions. How dangerous are all those concussions? The answer is complicated, and lies in how the brain responds when something strikes it.


The brain is made of soft fatty tissue, with a consistency something like jello. Inside its protective membranes and the skull’s hard casing, this delicate organ is usually well-shielded. But a sudden jolt can make the brain shift and bump against the skull’s hard interior, and unlike jello, the brain’s tissue isn’t uniform. It’s made of a vast network of 90 billion neurons, which relay signals through their long axons to communicate throughout the brain and control our bodies. This spindly structure makes them very fragile so that when impacted, neurons will stretch and even tear. That not only disrupts their ability to communicate but as destroyed axons begin to degenerate, they also release toxins causing the death of other neurons, too. his combination of events causes a concussion.

The damage can manifest in many different ways including blackout, headache, blurry vision, balance problems, altered mood and behavior, problems with memory, thinking, and sleeping, and the onset of anxiety and depression. Every brain is different, which explains why people’s experiences of concussions vary so widely. Luckily, the majority of concussions fully heal and symptoms disappear within a matter of days or weeks. Lots of rest and a gradual return to activity allows the brain to heal itself. On the subject of rest, many people have heard that you’re not supposed to sleep shortly after receiving a concussion because you might slip into a coma. That’s a myth. So long as doctors aren’t concerned there may also be a more severe brain injury, like a brain bleed, there’s no documented problem with going to sleep after a concussion.


The data show that at least among football players, between 50 and 80% of concussions go unreported and untreated. Sometimes that’s because it’s hard to tell a concussion has occurred in the first place. But it’s also often due to pressure or a desire to keep going despite the fact that something’s wrong. This doesn’t just undermine recovery. It’s also dangerous. 

Our brains aren’t invincible. They still need us to shield them from harm and help them undo damage once it’s been done.

From the TED-Ed Lesson What happens when you have a concussion? – Clifford Robbins

Animation by Boniato Studio