Resources – Medical Terminology

Terminology

This section of the website is dedicated to the education of my clients.  Far to often clients get overwhelmed and confused by the “terminology” of medical practitioners and facilities.  In an effort to reduce those anxieties and confusion I have created a terminology section on my site. 

If there is an terminology that you are confused about please email me and I will explain.

Email: Brent Furnish D.C.

Neural Plasticity

Neural plasticity (‘neural’ meaning nervous system, and ‘plasticity’ meaning ‘plastic’) is one of the essential principles of functional chiropractic neurology.

‘Plasticity’ is derived from the word ‘plastic’, which in scientific terms refers to a substance that can be shaped or modified by the application of a force.  In the case of the nervous system, it is now well established that new connections between nerve cells can be formed and existing connections can be modified.  This results in changes in the efficiency of circuits and pathways throughout the brain and nervous system – for better or worse!
The forces that ‘shape’ or ‘modify’ these connections and circuits are the electrical and chemical signals that are associated with nerve stimulation.  These signals trigger the expression of certain genes and proteins, which ‘build’ new ‘processes’ and ‘active zones’ on the nerve cell.
So what stimulates a nerve cell in the first place?

Any physical, mental or emotional event will result in activation of nerve cells in different regions of the brain and nervous system.

We could therefore say that ‘our experiences shape our brain’.

This also explains why different individuals respond uniquely to a similar event or stress.  Each individual’s brain adapts differently due to varying experiences over the course of their lifetime and due to a unique set of genes that contributes to the brain’s adaptability in the first place.

It is this adaptability of the brain that forms the basic premise of many of my treatment programs at Center for Alternative Medicine and Chiropractic.

Various mechanisms of brain adaptation help us to understand the changes that may occur in response to different brain injuries and subsequent rehabilitation approaches.  Grafman summarized four relevant mechanisms of neural plasticity, In: Conceptualizing Functional Neuroplasticity.  J Commun Disord 2000; 33:345-356. 

These included:
Homologous Area Adaptation – Transfer of specific brain functions to the equivalent region on the opposite side of the brain, or neighboring areas on the same side.

Cross-modal Reassignment – Certain areas of the brain may be ‘reassigned’ to a different sensory system to allow one system to become more effective at compensating for the loss of another.

Map Expansion – An area of the brain that processes a certain type of information or information from one area of the body will become larger if it used more often.  This results in a ‘take-over’ of neighboring areas of the brain.

Compensatory Masquerade – In some cases, the brain can learn to achieve a similar goal by using a different circuit or cognitive process.  For example, memorizing more details may to some extent compensate for a lack of understanding.

These forms of neural plasticity (or adaptive processes in the brain) should be considered when developing appropriate rehabilitation programs for individual patients and when interpreting the results of a clinical neurological or functional brain mapping assessment.

Receptors

“The nervous system obtains sensory information from the environment, evaluates the significance of the information, and generates appropriate behavioral responses” (Kandel & Schwartz. Principles of Neural Science – 4th edition. p335).  The ability of the nervous system to obtain information about the environment is due to the properties of ‘receptors’.  Receptors are connected with, or made from specialized cells that can transform information from the environment (within, or outside the body) into an electrical impulse that is then transmitted along a nerve.  The Nervous System is altered in some way every time a receptor is stimulated e.g. during treatment.  Examples of receptors include…

Visual receptors in the back of the eye that detect electromagnetic waves of different frequencies (perceived as colors and light).

Sound and motion receptors in the inner aspect of the ear that detect pressure waves from vibrating objects and movement of the head (perceived as different sounds and motion etc.).

Chemical receptors in the nose and tongue that detect different chemical compounds in the air or water (perceived as different smells and tastes).

Mechanical receptors that detect pressure, pain, movement, stretch or vibration in the skin, muscles and joints etc.

Due to the ability of nerve connections to be modified (a process sometimes referred to as ‘plasticity’), an individual’s perception of a particular stimulus could change from time to time depending on the health (or Central Integrative State) of a specific group of nerve cells.

An Overview of the Nervous System

The brain and the nervous system control all other organ systems in the body.  When the nervous system is not functioning optimally, problems may therefore arise in any of the following systems…

  • Cardiovascular (blood flow to and from the heart and brain)
  • Respiratory (breathing)
  • Gastro-intestinal (digestion & elimination)
  • Uro-genital (urination & reproduction)
  • Musculo-skeletal (muscle and joint function)
  • Vestibular (balance & spatial awareness)
  • Special sensory systems (vision & hearing etc.)

This is why a chiropractor with post-graduate training in chiropractic neurology will discuss and assess each of these aspects of your health.  The information gained from this assessment can give vital information regarding the overall health of the nervous system.  With a strong understanding about the behavior of a nerve cell in different regions of the nervous system, your practitioner aims to determine what the problem is and to monitor your response to treatment more accurately.

The nervous system can be divided up into several levels from top to bottom.  This includes the Brain, Brainstem, Cerebellum, Spinal Cord and Spinal Nerves.  The Cranial Nerves exit from the brainstem to supply muscles of the head and face and the organs of hearing, vision and balance.

The brainstem co-ordinates most functions and structures that guarantee our survival.  I.e. heart, lungs, digestion and sleep cycle and are also important for overall muscle tone and pain control.

The nervous system can also be divided into groups of cells from the midline to the outer regions.  Midline functions are more basic, but vital for survival, instinct and emotions, whereas the outer regions of the nervous system allow for more controlled and developed functions such as complex movements of the hands and feet, planning & organization and other complex thought processes.

The outer region of the nervous system developed in part from the midline areas as we grew from an embryo, and some of the connections between these areas are maintained through to adulthood.

Looking at how the nervous system developed is important for determining the normal relationships between different areas of the nervous system, and is the basis for the specific exercises that are sometimes given following the initial or subsequent Chiropractic Neurology consultations.

Development of the nervous system is dependent on both genetic and environmental influences.  Therefore, normal development and health of the nervous system is highly influenced by different exposures during the course of a lifetime, including social, familial, educational, medical/ chemical, dietary, and receptor based exposures (i.e. all the senses)

Having said the above, nervous system activity can also alter the expression of different genes, because a nerve impulse can trigger the production of proteins that change the activity of a specific gene.

 Vestibular System

The Vestibular Nucleus is a group of nerve cells that receive information regarding the space around you from receptors in the eyes and eye muscles, the vestibular balance organ of the inner ear and from joints and muscles (especially in the spine).  It is important for proper balance and spatial awareness that the vestibular system receives adequate information from all of these areas.  The diagram to the left shows the position of the balance and hearing organs deep in the ear (colored yellow).

The Vestibular System and another part of the nervous system called the Cerebellum are intimately related to one another.  Information from both of these areas is fed to the opposite side of the brain, especially in an area that is important for spatial or sensory awareness.  They also control posture and balance, coordination, the stabilizing muscles of the spine, eye movements (such as visual tracking), the muscles of the pelvic floor that are used to control and assist bowel and bladder function, and can heavily influence the Autonomic Nervous System (see below).  This is of great practical importance when developing a treatment plan to suit the imbalances in your nervous system.  The cerebellum has also been found to be important in cognitive processes – i.e. learning