When you see or hear that word many things can come to mind. You may think of
getting a cut, getting hit, or falling down. You may think about being rejected
in love or losing a family member. You might also think about being outcast at
school or work, or being robbed. I recently was robbed and I can assure you
that when I replay the incident I feel pain running down my arms. All of these
things cause pain, but are they different? What is the common thread that binds
them all together? You guessed it, your brain.
important 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 are
activated when physical and emotional pain are felt.
have been many theories of pain over the years. Aristotle and Plato both
believed that pain was not a sensation but emotion (Chen, 2011) (Moayedi,
Davis, 2013). This gave us the Intensive
Theory of pain. This said that pain came from an emotion that takes
place when a it is stronger than usual everyday occurences. In the renaissance
pain was believed to exist outside the body, as a possible punishment from God
(Moayedi, Davis, 2013). Later René Descartes who was a leading figure in
neuroscience stated that the body was like a machine, and that pain was dispensed
down nerve fibers until it reached the brain (Chen, 2011). This was the first
theory that made pain from spiritual to physical, and from the heart to the
brain (Moayedi, Davis, 2013).
there was the Specificity Theory of Pain. This theory stated that different
pain receptors and associated fibers that send signals to the pain center of
the 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 for
pain, such as it does for sight and hearing. This was influenced by what
Descartes had said earlier. There was the Pattern theory of pain, which did not
believe in specialized nerve endings, but rather that somaesthetic sensation
happened by a specific pattern of neural firings and the stimulus type and
intensity were a result of the firing of the peripheral nerves (Moayedi, Davis,
came the Gate theory, this theory states that large fibers can stop smaller
fibers from entering the pain gate. The small fibers carry pain stimulation, then
they enter the spinal cord (this is done through the dorsol horm), then these
signals are carried to the brain. (Moayedi, Davis, 2013) (Jenkner, 1995). They
called these fibers T cells. It was believed that larger fibers can have an
influence on smaller fibers that carry pain stimulation. It was believed that large fibers can stop
the small fibers from communicating to the brain, hence closing the gate.
However, if a large number of small fibers are activated they can cause the
gate to open. So, the greater the level of pain the less it is able to be
theories started moving in another direction. There is the
Neuromatrix model of
pain. This model states that there are many places in the brain and central
nervous 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 as
phantom limb pain. It states the parts that make up with pain web are the spinal
cord, brain stem, thalamus, the hypothalamus, amygdala, hippocampus, anterior
cingulate cortex, insular cortex, somatosensory cortex, motor cortex, and the prefrontal
cortex (Melzack, Katz, 2001). And finally, there is the Biopsychosocial model
of pain, which states pain is not just s physical phenomenon, but is also
brought on by social and psychological factors (Moayedi, Davis, 2013). This
theory explains the many different phenomena of pain, whereas some of the other
theories lack and understanding of certain causes of pain. What I find
interesting is that the first theories and last theories have on a level
combined to make the current theory. Not that pain is brought on by god, but
that can be brought on by emotion as well as physical injury. The purely
physical theories can’t explain certain forms of pain, such as emotional pain
or phantom limb pain.
Pain Without Tissue
limb 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 still
unknown, but it is believed to originate from the central nervous system or the
peripheral nervous system (Flor, Diers, Andoh, 2013). One theory suggest that the loss
of neural input allows for the intrusion of neighboring cortical regions into
the former processor area of the limb in primary sensorimotor cortex (Flor, Diers,
Andoh, 2013). Mirror therapy is used in phantom limb pain, this is
where they put a mirror next to the limb so the patient can feel that their
limb is there once again and that no pain is coming to it by movement of the
reflected limb (Foell,,
et al., 2013).