What happens when you get a concussion, biologically? For years, I have had this question. Doctors didn’t have the time nor the simple words to explain it to me. The medical explanations on the Internet were far too difficult to read. But I had a broken brain, and I wanted to know why.
This blog post is for all of you who are looking for answers, too. Understandable, no-nonsense and relatable, from 1 survivor to another.
What is a concussion?
Let’s start at the beginning.
A concussion is a mild traumatic brain injury (mTBI). You may have sustained your concussion from a sports accident, you may have been the victim of violence or you may have fallen from the stairs. Or, like me, you may have gotten a whiplash injury from an accident in traffic.
Whatever the cause, you feel inexplicably unwell. And this isn’t strange at all, if you consider what happened to you at the moment of impact.
How a concussion happens
Around the moment of impact, probably 1 or several events happened to you:
- Your experienced direct impact to your head
- Your skull was broken or maybe even penetrated because of 1.
- Your head made a jerking movement (causing a so-called acceleration and deceleration movement)
- There was a blast and any of the above options happened to you because of it
Contrary to popular belief:
- Your head didn’t need to touch something
- You didn’t need to lose consciousness
- Doctors often can’t physically see mTBI on scans (but ALWAYS have them check!)
All of these events are BIG. And most of us know very well how big they are because of all the symptoms that follow.
Recognizing concussion symptoms
The easiest way to recognize you have a concussion is that you just know something is off. You feel inexplicably unwell. Examples of symptoms that you might experience are:
- Major headaches
- Problems with concentration and memory
And these are only a few of many things that might be going wrong since your incident. These symptoms are often temporary, but can also linger for years.
This was the case with me: I had post-concussion syndrome. This means that I experienced lingering symptoms 3 weeks after my accident. If you have the same, please know that it isn’t as chronic as it sounds.
Doctors told me my brain would never heal, that my brain injury had lasted too long. But even after this grim prognosis, I made a full recovery. Because there is so much more to our beautiful brains than doctors know about or have yet to accept.
My brain has MORE THAN recovered, and I’m here to help you do the same.
Why understanding what happened is important
To make a full recovery, it’s very important to know what physically happened to you. It’s already known that concussion patients want to understand what their injury actually is. Not only does it help you understand the way you feel: it also unlocks the keys to what you need to do to repair your broken brain.
How a healthy brain works
To grasp what happened to your brain, we first need to understand how a healthy brain works. And this is what doctors mean if they say “physiology”. Meike and I are going to make it as easy as we can.
Let’s dig in!
Your brain is built up by different regions that each have their own function. You can see them as different employees in a shop. One takes care of customer questions, the other unpacks new deliveries, and so on.
In your brain, some regions facilitate thinking for example. Other regions regulate processes such as breathing and sleeping.
The brain cells
The different regions of the brain are build up by roughly two types of cells:
- glial cells
- and nerve cells (also called neurons).
Glial cells have a supportive and protective function for neurons. We’ll get back to them in a bit.
Neurons are key players in your brain’s activity. You can see them as players in a football game: without them, the ball wouldn’t be moving. Likewise, without neurons, communication signals wouldn’t be moving in your brain.
To understand your concussion, it’s very helpful to understand more about how neurons work. Bear with me as we dive even deeper into the workings of your brain.
Your neurons are made up of 4 parts:
- a cell body,
- an axon,
- and the axon terminal.
The dendrites are the antennas of the neuron. They pick up signals from other neurons.
The cell body
Inside the cell body, you can find a nucleus. That’s where DNA (the genetic material) is located. You can see DNA as a cookbook holding the instructions for a recipe. DNA holds the instructions for all processes in the cell.
The axon is a long structure. It can be seen as a road from one communication point to another, like an old telephone line! And you know how an electrical cable is protected with a PVC sheath?
The axon is protected by glial cells in the same way. These glial cells form protective cushions of so-called myelin sheaths.
The axon terminals
The axon terminals send signals to the dendrites (the antennas) of other neurons. The structure that is formed by an axon terminal and a dendrite is called a synapse.
How neurons pass around messages
A neuron, with all its parts, is a kind of highway. And together, all neurons form a whole continent of interconnected highways! To connect with each other, neurons need 2 things.
Of course, they need a message to pass on. In brain terms, this is an electrical signal. The message travels over the different parts of the neuron.So, it moves from the dendrites, through the cell body, over the axon to the synapses.
From the synapses, the electrical signal needs to be passed onto the next neuron. In the synapses of the first neuron, the electric pulse triggers the release of neurotransmitters. These are communication molecules.
And these neurotransmitters pass on the message to the dendrites of the second neuron. This message instructs the second neuron what to do next. And so the second neuron can also generate an electric signal and pass on the message.
The transport of neurotransmitters
Neurotransmitters are made in the body of the neuron. The neuron knows how to do this because it has the recipe inside the DNA cookbook.
Once produced, the neurotransmitters are transported in vehicles. These vehicles move the neurotransmitters through the axon, toward the synapses. There are special roads for these vehicles to travel on. These are called the microtubuli, and they are located in the axon.
TBI can disturb the passing on of messages and newly formed neurotransmitters through the axon. So that’s what we are going to have a look at right now!
How a concussed brain works
Now let’s have a look at the processes in your body that are related to your concussion. This is what doctors call concussion pathophysiology.
Don’t worry, it’s just another hard word with an easy explanation. It means: what happened in your brain and body since you sustained your concussion?
What happens during a concussion?
During a concussion, your brain heavily moves within your skull. Compare it to shaking a bit of jelly inside a glass jar. The jelly bounces against the glass, it turns within the glass and it can also tear.
Roughly put, your brain experienced about the same inside your skull. But to really understand what happened to your brain, we have to dive deeper to a much smaller level.
Scans can’t always see brain damage
As you may have experienced yourself, doctors can’t always see your concussion. That’s because conventional imaging techniques are often used to analyze the brain. You probably know computed tomography (CT) and magnetic resonance imaging (MRI).
CT scan usually don’t reveal abnormalities in the brain after concussion, and MRI only shows concussion in 1/3 of patients. It is important that you do have a scan, though, to exclude that there are no medical emergencies such as hematomas (which means bleeding in the brain).
What causes concussive symptoms?
The above indicates that the cause of mTBI lies at a much smaller level than is visible on CT or MRI scans. The precise mechanism isn’t fully explained by science yet. But: researchers have found several leads that together may open the door to fully understanding what causes the health complaints after a concussion.
Learning from CTE and severe TBI
Concussions are being studied very actively at the moment. In fact, never has there been so much large scale and ongoing research as right now, and it is the start of so much more.
Until about 2014, if we wanted to learn about concussions, we had to look at research done in the fields of chronic traumatic encephalopathy (CTE, which is caused by multiple concussive injuries following each other) and moderate or severe traumatic brain injuries (TBI).
Since 2014, however, multiple enormous studies – CENTER-TBI, TRACK-TBI and Care Consortium – have started to zoom in on concussions. And that’s how we now have a lot of findings on concussions, and what cause them.
Diffuse axonal injury
The mechanical force of a concussion stretches and can even tear the long thin axons of a neuron. This is a process called diffuse axonal injury and this shearing has been shown to happen in white matter microstructure in mice and rats.
It’s actually a series of events. When an axon is overstretched, the microtuli motorways can disrupt. (You remember them? They are the roads for neurotransmitters that help neurons communicate.) This means that less or no transport is possible over those roads.
Next, the axons can bulge and also leak. These events together can lead to the axon detaching and the dysfunction of the synapses.
In short: diffuse axonal injury leads to less messages being (successfully) passed on in your brain.
Another thing that likely happened to your brain when you got your concussion is neuroinflammation. We say “likely”, because neuroinflammation certainly happens in patients with severe and moderate traumatic brain injury. Research is just now zooming in on patients with mild traumatic brain injuries (concussions), and indeed, neuro inflammation has been observed. However, these studies are still in their infancy and that is why we say inflammation “likely” occured.
(Check out this Concussion Foods guide to learn about anti-inflammatory foods that majorly helped Melanie during her recovery.)
Neuroinflammation is an inflammation of a part of the nervous system. After sustaining a concussion, immune cells are activated in the brain. These activated cells release a series of inflammatory related molecules. These molecules can cause dysfunction of certain processes in the brain. They are correlated with several changes in behavior and cognition after a concussion.
Also, those dysfunctions can eventually lead to less communication between neurons. What the exact mechanisms are behind inflammation and concussion symptoms is still being researched.
What happens when you get a concussion?
In this post you have learned that diffuse axonal injury is a central process in your concussion. It is accompanied by other effects, like neuroinflammation. More (exact) details of what happened to your brain when you got your concussion are currently being researched.
What you experience is real
It might not have been possible to get a concussion diagnosis for you. That’s because conventional scans can’t always find that something is wrong inside your brain. Doctors may tell you – like they told me over and over again – that there is nothing wrong with you and that this is good news. But this doesn’t mean that it isn’t there. What you feel and experience is real.
You know yourself best.
You are your own expert.
You know if something is off.
You know you have a concussion if you have one.
Really, you know. When it comes to diagnosing (and curing!) your concussion: trust yourself. Yes, even more than experts. This is one of the things that I explain in the free audiofile 3 things I wish I knew while recovering from my concussion.
Now we’d like to hear from you
Have you been able to get your concussion officially diagnosed? And how has the medical process and interaction with doctors been for you? Let us know by leaving a comment below.