User:Bwalsh5/sandbox

Pain Tolerance
The perception of pain that goes in to pain tolerance has two major components. First is the biological component—the headache or skin prickling that activates pain receptors. Second is the brain’s perception of pain—how much focus is spent paying attention to or ignoring the pain. The brain’s perception of pain is a response to signals from pain receptors that sensed the pain in the first place.

Sex
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Passive or active support
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Age
Age and pain tolerance are relevant especially in the elderly because if their pain is detected too late, they run the risk of greater injury or delayed treatment of disease. However, current knowledge shows that pain tolerance does not show substantial change with age. Only pain threshold shows an effect: it increases with age.

Ethnicity
In laboratory studies African-americans have shown a lower pain tolerance in comparison to Caucasians.

Psychological factors
Patients with chronic mood disorders show an increased sensitivity to pain. This is not surprising because many of the brain pathways involved in depression are also involved in pain. These disorders weaken the cognitive aspect of pain and thus lower pain tolerance. These effects are worse in unipolar compared to bipolar disorders, although both perceive pain significantly worse than people without a mood disorder. The lowest pain tolerance was seen in participants that were currently experiencing a major depressive episode. Unfortunately, lower pain tolerance associated with depressive symptoms can increase thoughts of suicide.

Hand dominancy, or handedness
One way to measure pain is to have participants place their hand in ice cold water. Their pain tolerance can then be measured based on how long they are able to keep their hand submerged before taking it out. One study used this technique to compare pain tolerance in dominant and non-dominant hands. One finding was that dominant hands showed a higher pain tolerance than non-dominant hands. Right-handers could withstand pain longer in their right hand than their left hand while the opposite was true for left-handers.

Neonatal injury
Nociceptive pathways are pathways in the brain that send and receive pain signals and are responsible for how we perceive pain. They develop before a baby is born and continue to develop during the critical period of development. It was once thought that because infants’ nociceptive pathways in the brain were still developing, they could not feel pain. However, infants can feel pain and infant surgeries providing early pain experiences can alter the brain’s tolerance for pain later in life. It can do so by increasing number of A fibers and C fibers—two types of pain receptors—located in the area where injury occurred and by reducing pain tolerance in the areas where incision has occured. This reduction in pain tolerance is seen in male rats even when they are adolescents. In those rats, the area of their brain where an incision was made as an infant remains hypersensitive to pain thereafter. This effect was not seen as prominently in female rats.

Association and dissassociation
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