Neurobiology of Concussion - Part 1

Intro to Neurobiology...

You don’t need to be a genius neurosurgeon to understand the basics about the structure of your brain and what generally happens after a concussion injury.  There’s no need to be intimidated - we’ll make it painless and break it down for you over a few articles.  We believe having some knowledge about what’s happening inside our head can be empowering and benefit your recovery.  .  Here’s an overview of what’s in store:

  • Part 1 - Quick anatomy lessons

  • Part 2 - How the brain is organized

  • Part 3 - The effects of a concussion injury

  • Part 4 - Symptoms explained

 

Neurobiology of Concussion Part 1 - Quick biology lessons:

Before we dive deeper into the underlying neurobiology of concussion, we need to get a few definitions out of the way:

Neuron (sometimes called nerve or brain cells)

Neurons are the basic building block of your brain and nervous system.  There are about 80-100 billion of these cells in your brain, each making thousands of connections.  

Glial cells 

Glial cells are the support cells of your nervous system that are responsible for providing structure, insulation, nutrients and help with cleaning / healing.

Brain

The brain is a little too complex to describe in a few sentences.  It is the main control centre of the body and is involved in basically all systems including the nervous system, endocrine system and automatic body functions.  There are some great resources out there already.  To learn more we encourage you to play around with the awesome interactive brain model from FINR and watch a few videos below.

Nervous system 

Your brain doesn’t exist in isolation, disconnected from the rest of the body.  The brain stem becomes the spinal cord as it travels down, branching into all of the nerves that run throughout your body which control body functions and carry information back to the brain.  The whole thing really acts as one and is referred to as the nervous system. 


 

Neuroimmune System 

The immune system plays a very important role in the brain and nervous system, protecting from disease and healing after injury.  An immune response and inflammation (not the same thing as swelling) does occur in the brain after concussion injury and is a normal part of healing.  However, prolonged inflammation might contribute to continued symptoms.  The brain also plays a role in controlling aspects of the immune system too.

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Endocrine System

The endocrine system produces hormones and other signalling compounds that control much of the body including metabolism, stress response, growth and development, sleep, sexual function and more.  Three major endocrine organs exist in the brain: the hypothalamus, pineal and pituitary glands.  These three areas basically control the remainder of the system directly or indirectly.  A concussion can sometimes cause an issue in these systems.


Circulatory & Lymphatic System

There are thousands of blood and lymphatic vessels in the brain that carry blood and nutrients to the individual brain cells and take away waste.  The brain and spinal cord also have their own circulatory system of cerebrospinal fluid.  The skull and spine are filled with the cerebrospinal fluid which cushions the brain and spinal cord.  There is a filter between your blood and the cerebrospinal fluid which is called the blood brain barrier.  Concussions can affect how well the circulatory system works but don’t normally cause damage to larger blood vessels or cause observable brain bleeding.

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Other Resources:

If you want to learn more neurobiology, check out these great 2-minute neuroscience videos from neuroscientificallychallenged.com.


REFERENCES

  1. Barkhoudarian, G., Hovda, D. A., & Giza, C. C. (2016). The Molecular Pathophysiology of Concussive Brain Injury–an Update. Physical medicine and rehabilitation clinics of North America, 27(2), 373-393.
  2. Blennow, K., Hardy, J., & Zetterberg, H. (2012). The neuropathology and neurobiology of traumatic brain injury. Neuron, 76(5), 886-899.
  3. Giza, C. C., & Hovda, D. A. (2014). The new neurometabolic cascade of concussion. Neurosurgery, 75(0 4), S24.
  4. Mota, B., & Herculano-Houzel, S. (2014). All brains are made of this: a fundamental building block of brain matter with matching neuronal and glial masses. Frontiers in neuroanatomy, 8, 127.
  5. Patterson, Z. R., & Holahan, M. R. (2012). Understanding the neuroinflammatory response following concussion to develop treatment strategies. Frontiers in cellular neuroscience, 6, 58.
  6. Plesnila, N. (2016). The immune system in traumatic brain injury. Current opinion in pharmacology, 26, 110-117.
  7. West, T. A., & Sharp, S. (2014). Neuroendocrine dysfunction following mild TBI: When to screen for it. The Journal of Family Practice, 63(1), 11