If any one of them is abnormal the outcome may be flawed or even absent. There are many points where bad information can enter the system, just as there are many places where your television image can be messed up. What your sensory cortex actually feels for you is a combination of all the things that happen from the nerve ending in the skin, muscle, bone or other tissue, through all the connecting nerves, all the way to the sensory cortex. Just as there are many complex circuits between the camera and television screen, there are incredibly complex neuro circuits between the sensory nerve fiber and the sensory cortex. These complex circuits help control what you feel and help you make use of the information that you receive.
Nerves conduct information much like television cables transmit images.
It is done by a series of electrical discharges along the nerve fibers. The nerve axon from your toe runs all the way to the spine, where it connects with other nerve fibers. When the electrical signal gets to the end of the nerve axon, the impulse is transmitted to the next nerve by release of neurotransmitter substances like acetylcholine. The acetylcholine stimulates the next nerve, which acts like a relay runner and picks up the message can carries it along the spinal nerve tracts toward the brain. They are also affected by a number of chemicals like narcotics, sedatives, muscle relaxers, anti-seizure drugs, local and general anesthetic agents, and many others.