In this essay, I am going to describe and explain evidence
that shows pain perception is not entirely dependent on
physical injury. I will explore and analyse different explanations and views
surrounding pain perception and physical injury. There have been a number of historical ideas,
contributions and theories to explain the physiological basis of pain. Before these theories, people thought that pain was a direct
consequence of physical injury, however, it is now considered that pain is a
combination of physical and psychological factors.
René Descartes was a French philosopher in the 17th century. In 1664,
Descartes proposed a theory called Specificity Theory. His theory proposed that the body has a separate sensory
system for pain and that this system has its own specific receptors for processing
pain signals. Descartes proposed that when a noxious event stimulated a pain
receptor, a signal travelled through hollow tubes to the pain centre in the
brain, where it was perceived as pain. This theory suggests that more pain is experienced
when the event is more noxious. Descartes also suggested that the intensity of
pain was linked to the amount of tissue injury. I believe that this element of
his theory is accurate when applied to certain types of injury and acute pain,
for example, a needle prick to a finger would cause less pain than a large cut
by a knife as there would be more tissue injury, which would be more painful.
In contrast to Descartes Specificity Theory, Ronald Melzack, a Canadian psychologist
suggested that pain perception is a combination of sensory experience and psychological
gates that either increase or decrease pain perception. For example, a person
have pain, but they are not really aware of it because they are distracted by
something that demands their attention. Another example would be a soldier who
is fighting in a battle, may carry on through the pain, despite suffering a substantial
injury. It could also be said, that people feel pain more when they are
thinking about it and if it is playing on their mind.
The Gate Control Theory provides a combination of physiological and
psychological pain perception. The theory proposes that the nerve impulses
produced by pain, travel through a series of gates on the way to the brain, and
that these gates can be influenced and be opened or closed by the flow of
information. Melzack suggest that little cells in the spinal cord could
function as a gate and close off the pain information. For example, the gate may
be opened by a sprained ankle, however the gate can be closed by taking
medication to relieve the pain. From a personal point of view, I have permanent
nerve damage in my leg, which causes substantial pain and discomfort, I can
however, manage this pain by having medication and also counter-stimulation
through massage, which would be ‘closing’ the gate to prevent this pain.
Melzack also reviewed
evidence of phantom pain. Phantom pain is a condition where pain is caused by a
limb or part of a limb that is no longer there. After a person has had a limb
amputated, the person continues to have an awareness of the limb and feels pain
from it. If the limb is not there, it means that there must be another route
for pain perception.
Pain is not experienced merely by having a physical injury, there are a
number of factors which can cause people to feel emotional pain without having
an injury to their body. Examples of this can include bereavement and mental
health. Closing the gates can ease this
pain. Factors that can do this include counselling, relaxation and activity involvement.