When you see or hear that word many things can come to mind. You may think ofgetting a cut, getting hit, or falling down. You may think about being rejectedin love or losing a family member. You might also think about being outcast atschool or work, or being robbed. I recently was robbed and I can assure youthat when I replay the incident I feel pain running down my arms. All of thesethings cause pain, but are they different? What is the common thread that bindsthem all together? You guessed it, your brain. It isimportant to look at all forms of pain, as many are experienced very similarly.We will look at some studies that show the same areas in the brain areactivated when physical and emotional pain are felt.
Theoriesof Pain Therehave been many theories of pain over the years. Aristotle and Plato bothbelieved that pain was not a sensation but emotion (Chen, 2011) (Moayedi,Davis, 2013). This gave us the IntensiveTheory of pain. This said that pain came from an emotion that takesplace when a it is stronger than usual everyday occurences. In the renaissancepain was believed to exist outside the body, as a possible punishment from God(Moayedi, Davis, 2013). Later René Descartes who was a leading figure inneuroscience stated that the body was like a machine, and that pain was dispenseddown nerve fibers until it reached the brain (Chen, 2011).
This was the firsttheory that made pain from spiritual to physical, and from the heart to thebrain (Moayedi, Davis, 2013). Thenthere was the Specificity Theory of Pain. This theory stated that differentpain receptors and associated fibers that send signals to the pain center ofthe brain and then the brain produces the feeling of pain (Chen, 2011) (Moayedi,Davis, 2013). It was believed that the body has specific sensory system forpain, such as it does for sight and hearing. This was influenced by whatDescartes had said earlier. There was the Pattern theory of pain, which did notbelieve in specialized nerve endings, but rather that somaesthetic sensationhappened by a specific pattern of neural firings and the stimulus type andintensity were a result of the firing of the peripheral nerves (Moayedi, Davis,2013).
Thencame the Gate theory, this theory states that large fibers can stop smallerfibers from entering the pain gate. The small fibers carry pain stimulation, thenthey enter the spinal cord (this is done through the dorsol horm), then thesesignals are carried to the brain. (Moayedi, Davis, 2013) (Jenkner, 1995). Theycalled these fibers T cells. It was believed that larger fibers can have aninfluence on smaller fibers that carry pain stimulation. It was believed that large fibers can stopthe small fibers from communicating to the brain, hence closing the gate.However, if a large number of small fibers are activated they can cause thegate to open. So, the greater the level of pain the less it is able to beblocked.
Thentheories started moving in another direction. There is theNeuromatrix model ofpain. This model states that there are many places in the brain and centralnervous system which produce pain, not from tissue damage (Melzack, Katz, 2001).This will help explain pain that has no relation to any tissue damage such asphantom limb pain. It states the parts that make up with pain web are the spinalcord, brain stem, thalamus, the hypothalamus, amygdala, hippocampus, anteriorcingulate cortex, insular cortex, somatosensory cortex, motor cortex, and the prefrontalcortex (Melzack, Katz, 2001). And finally, there is the Biopsychosocial modelof pain, which states pain is not just s physical phenomenon, but is alsobrought on by social and psychological factors (Moayedi, Davis, 2013). Thistheory explains the many different phenomena of pain, whereas some of the othertheories lack and understanding of certain causes of pain. What I findinteresting is that the first theories and last theories have on a levelcombined to make the current theory.
Not that pain is brought on by god, butthat can be brought on by emotion as well as physical injury. The purelyphysical theories can’t explain certain forms of pain, such as emotional painor phantom limb pain. Pain Without TissueDamage Phantomlimb pain is the phenomenon where pain is felt in the amputated limb of a body.
Phantom limb pain occurs in 80% of amputee patients (Flor, Diers, Andoh, 2013). The causes of this are stillunknown, but it is believed to originate from the central nervous system or theperipheral nervous system (Flor, Diers, Andoh, 2013). One theory suggest that the lossof neural input allows for the intrusion of neighboring cortical regions intothe former processor area of the limb in primary sensorimotor cortex (Flor, Diers,Andoh, 2013). Mirror therapy is used in phantom limb pain, this iswhere they put a mirror next to the limb so the patient can feel that theirlimb is there once again and that no pain is coming to it by movement of thereflected limb (Foell,,et al.