Brain injury changes who we are.

The living brain is the consistency of jello. Part of the soft brain tissue, called axons, extends across different layers of the brain from the gray matter (cerebral cortex) to the white matter (subcortical area). Brain tissue has different densities (weights), rigidity and cellular architecture, and is located at varying distances from the center of a given rotation. When there is trauma to the brain, the different layers of the brain slide across each other causing unnatural stresses on the axons.

Here are two animations from YouTube illustrating what happens when there is trauma to the brain. http://youtube.com/watch?v=gCMS8aOmK1M; http://youtube.com/watch?v=AmAML1-F2LE. 

Axons are like wires connecting the nerve cells (called neurons). It is estimated there are about 100 billion neurons in each single human brain. At the connections between the neurons there is a tiny gap (called a synapse) into which chemicals (called neurotransmitters) are released allowing the messages between neurons to take place.

There are 100 to 10,000 connections between each neuron in the brain. Based on an average of 1000 synapses for each neuron, a conservative estimate, there are about 100 trillion (100,000,000,000,000) connections in your brain. There are more neurons, let alone connections, in a single human brain than there are telephone wires in the entire phone system on Earth. 

The operation of the human brain can also be thought of in simple terms. Sending messages to and from the brain is like turning on lights: The axons, as the wires, transmit electrical signals to the synapses, as the switches, where chemicals called neurotransmitters are released to turn on the neurons, as the lights.  To send messages from one neuron to another going into and out of your brain you need electrical and chemical stimuli throughout an incomprehensibly huge network of healthy axons and synaptic connections.

The analogy to lights is just to explain the phenomenon. Your brain is a black box. What you see, hear and feel is electrochemical activity in the form of sequences of patterns of axons and synapses firing throughout the brain. There are no actual lights, sounds or sensations coming into the brain. If the axons are not working, or are not working well to transmit the electrical signals, then neither is your brain.

When trauma to the soft brain tissue occurs, whether from falls, blows, crashes or blasts, this often causes stretching or tearing of axons resulting in the nerve impulses not transmitting or transmitting less efficiently. It is as if each time you want to turn on the lights in a room in your home you have to try the switches in several different rooms to do so, sometimes without success. Also, bruising of brain tissue, principally at the front and back of the brain, often occurs with trauma, especially of the whiplash variety, as the soft brain is thrust back and forth within the confines of a hard bony skull. See the YouTube animations, above.

One of the facts of traumatic brain injury is that the condition may worsen for several days or longer after the trauma occurs. The reason for this delayed deterioration of brain tissue is explained by the National Institute of Neurological Disorders and Stroke (NINDS) of the National Institute of Health (NIH):

"One of the most pervasive types of injury following even a minor trauma is damage to the nerve cell's axon through shearing; this is referred to as diffuse axonal injury. This damage causes a series of reactions that eventually lead to swelling of the axon and disconnection from the cell body of the neuron. In addition, the part of the neuron that communicates with other neurons degenerates and releases toxic levels of chemical messengers called neurotransmitters into the synapse or space between neurons, damaging neighboring neurons through a secondary neuroexcitatory cascade. Therefore, neurons that were unharmed from the primary trauma suffer damage from this secondary insult. Many of these cells cannot survive the toxicity of the chemical onslaught and initiate programmed cell death, or apoptosis . This process usually takes place within the first 24 to 48 hours after the initial injury, but can be prolonged."

Shearing, tearing and bruising of brain tissue, and the assault of chemicals within our brains released by our bodies as a result of the initial trauma, is especially damaging in the front part of the brain, called the frontal lobes. Injury to the frontal lobes is particularly significant because this part of the brain makes us uniquely human. 

The purpose of the frontal lobes is often described as our “executive function.” It is the part of the brain most responsible for our planning, organizing, sequencing, decision-making, judgment, motivation and initiation. It is also the principal part of the brain controlling human moods, feelings and emotions (which arise in a more primitive part of the brain in the subcortical area called the limbic system). 

If the entire brain is an orchestra, with different sections for violins, cellos, flutes, horns, piano, drums and all, the frontal lobes are the conductor who keeps everyone playing together to make beautiful music. Trauma to the brain changes who we are.

It is time to break the silence of the traumatic brain injury epidemic.