Environmental controls affect the nervous system based upon the nervous system to respond to the environmental entity. There are constant developmental changes in the brain that will determine the ability of the cortex to respond to an environmental stimulus or event. A nervous system without environmental stimulation is like an automobile without fuel. It may exist, but not as a functional entity. The thalamus is that area of the brain where sensation is perceived. The medial geniculate portion of the thalamus is where hearing is perceived. The lateral geniculate portion of the thalamus is where vision is perceived. The nucleus ventralis posterior is the largest area of the thalamic nuclei and is where all sensation from spinal joints is perceived. Central integration is a term that means how well your brain is working. Hemisphericity is when you develop an inequality of function from one side to another. Manual perimetry testing is a simple and inexpensive method to determine how well your brain is functioning. The results of blindspot mapping should be equal. Changes in function from right to left lead to dysfunction which can lead to a variety of disease conditions. The importance of this simple diagnostic tool has a great neurologic significance in determining how chiropractic care should be directed in order to maximize your human potential.
Patients that have unequal blind spots can present with a variety of symptoms. Realize that if you have a large blind spot in your left eye compared to your right eye you cannot perceive vision as well from that left eye and you will have to tilt your head to compensate for this. The changes in head position have major effects on body mechanics. Patients that have a large blind spot often remark that they have a tendency to walk into walls or worst, end up in our office because they were involved in an auto accident because they didn't see the other car coming.
To make matters worst, people that are in an accident and do not receive proper care for their injuries often find that they keep getting into more accidents because their blinds spots continue to worsen and they suffer an increasing poor state of central integration.
Dr. Fred Carrick, who is my neurology professor, recently published his dissertation, NEUROPHYSIOLOGICAL IMPLICATIONS IN LEARNING in order to fulfill his requirements for the degree of Doctor of Philosophy in Education. He did a study on five hundred participants where blind spot mappings were produced with changed noted before and after chiropractic adjustments. Pre and post adjustment changes in the blind spot were mapped with ease in this research project. Chiropractic adjustments have a direct effect on brain function and this has been well documented in recent testing of neurological function. The development of the thalamus and its ability to become an Integrator is pivotal in the understanding of central integration of multimodal environmental potentials such as vision and joint reflexology. Anytime dysfunction in a system exists there is a high probability for disease processes to occur. Symptoms may present as various pain conditions or internal organ problems. Dr. Carrick dissertation explores aspects of developmental brain and its relationship to learning and behavior which will be addressed in our next newsletter.
Changes in central integration can result in a probability of altered perception. One of the theories that Dr. Carrick referred to in his book dealt with seating positions of students in the classroom. It would be wise for a student with a left large blind spot to sit on the left side of the room rather than the right, because sitting on the right would cause decreased perception and limited integration which would overall decrease learning potential. One could reposition the student to the appropriate area of the classroom or consult a chiropractor for care that would promote balance of these blind spots and improve central integration for the capacity of your brain.
A sheet of photoreceptors consisting of rods and cones are found on the retinal surface of your eye. Each of our eyes has a region in our eye called the optic disc where there are no receptors (rods or cones). The optic disc area is where the optic nerve and blood vessels enter and account for our physiological blind spot. Our visual experiences do not typically include an awareness of the blind spots resulting from the absence of receptors in these regions because one eye will compensate for the other.
In our patient newsletter, we enclosed a simple way for you to experience your blind spots. For an actual manual perimetry test and comprehensive neurological evaluation, contact our office at 602-951-5006.
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(Updated 01 JUN 97)