When a child is born the brain has basically developed all of the brain cells it will ever develop. As brain cells become injured or die they are not generally replaced, but rather routed around by a process called neuroplasticity.
The newborn brain is complete with about 100 billion cells or about a total of 3% of the total brain mass. The mature brain contains about 100 trillion connections which comprises 97% of the brain mass. The fact that the brain increases in size as the child matures is due to advancing neuro-connections. These neuro-connections are made as the child is stimulated and learns to interact in his environment and develops processing and learning skills.
No one child's brain is ever stimulated exactly the same as another child's brain. All normal brain development follows distinct and predictable developmental patterns. A child's individuality lies in part with the specific input of stimulation from the child's environment.
Stimulation by way of sensory input and increasing the processing skills of the child is what brings about neuro-organization and also produces organized neuro-connections that increase the brain's size and weight. Neuro-organization can also be stated as neuro-efficiency, or the effectiveness that the brain can receive, process, store, retrieve and utilize any given input to the brain.
Neuro-plasticity is an innate process by which healthy brain cells will take over the function of injured or dead cells and damaged connections. There is always more than one center of the brain that can take over the function of lost or impaired centers. Stimulating therapies will accelerate this "rewiring" of the brain by providing sufficient opportunity for the brain to establish new connections to healthy brain centers.
In neurodevelopment there are receptive functions and expressive functions. Receptive functions are tactile, auditory and visual input. Expressive functions are language, motor skills and academics. The expressive or output functions of the brain (i.e. language, motor skills, and academics) are direct indicators of receptive function, neuro-efficiency and processing skills. A brain that is limited in opportunity by either lack of stimulation or injury will have limited output functions. This brain will have a reduced number of neuro-connections and limited function as opposed to the healthy brain that is receiving plenty of clean and organized input (hearing, feeling, and seeing). Output functions of the brain can be stimulated with organized activities and therapies that can help produce targeted neuro-connections. These activities or therapies need to have specific intensity and frequency to be most effective. Random input may be mildly stimulating but will not produce specific results (like a brightly colored playroom or classroom without specific organized activities required to improve function.
Hemispheric dominance is an integral part of brain structure. This is where one hemisphere of the brain is in dominant control. In the case of mixed dominance there are a lot of inefficiencies in brain organization that results in information being transposed from one side of the brain to the other as in dyslexia. Other inefficiencies will be un-coordinated motor skills function low processing abilities, long term memory shortfalls and emotionality. (That will be the topic of my next article!)
Neuroplasticity
For years researchers have attempted to map the human brain. One thing they have found is that the part of the brain that performs a specific function can change in the space of a few weeks making the process of mapping very difficult. This makes every map of the same brain different from one time to the next. The reason for this is neuroplasticity.
Neuroplasticity is an innate ability that every central nervous system has. In the case of a traumatic brain injury, this process works where a healthy part of the brain and central nervous system can take up the function of an injured part. The key to this happening is to make the opportunity available for rerouting an injury to happen. This can happen in physical therapy when the brain is given the opportunity to rewire around a damaged area by providing the desired function that sends the signals to the brain. The brain will then begin to wire in a new pathway if the frequency, intensity, and duration of the therapy are adequate.
I know this principle of neuroplasticity from both my personal experience and clinical experience. I personally suffered from the neurological ravages of polio as a child, which did damage to my spinal anterior motor horn neurons and also a de-myellination to the pons level of my brain. I was left unable to walk. At the age of four I was given the opportunity to learn how to walk with adequate intensity and duration of a simple process called patterning. The walking function of the brain is located generally in the pons level of the brain. One area of my brain injury was on the pons level of the brain. Through the miracle of neuroplasticity, another part of my brain took up the function of walking which gave me a "cortical walk" instead of a walk from the pons level. Obviously the best part of the brain to use would have been the original pons of the brain. Unfortunately, the patterning I received only patterned my legs and not my arms and upper body and was not thorough enough to give me a perfect walk. My walking was crude and my running was very sloppy so consequently I fell down a lot but I was walking!