It has been said that one of the aspects of healthy living is freedom from pain. Technically speaking, this is when the amplitude of receptor potentiation is less than necessary to stimulate the second order neuron of nociception. To continue on our education of the nociception afferent system, there are three major ascending pathways. When dealing with head and facial pain, these scenarios take on a different perception to the patient than pain of the elbow.
People tend to tolerate more of the latter.
The concomitants of head and facial pain seem to be different than other localization of pain. With head and facial pain, as with a classical migraine, localization appears to be shared by two different nerves. So to perceive these areas of pain simultaneously, both sensory nerves thus stated would be brought to the threshold. Since pain modulation could be segmental or suprasegmental, the correlation exists between a reduction in this modulation and reduction in sensory receptor potentials. Chiropractically speaking, any therapeutic activity that increases this sensory perception will cause a presynaptic inhibition at the dorsal horn, as well as the release of enkephalins and endorphins caudally and rostrally.