Pain is often described as an uncomfortable, unpleasant and sometimes distressing feeling often triggered by certain stimuli.

A study conducted in 2016 has revealed that pain is more than simply a matter of nerves. This study was performed by researchers from the Division of Neurophysiology at MedUni Vienna's Center for Brain Research.

According to Jürgen Sandkühler, who is the head of the division, the activation of glial cells which are commonly found in the human brain and spinal cord can result in a pain-amplifying effect. The pain could spread to other body parts, despite those parts being previously unaffected.

Sandkühler also stated that the activation of glial cells can be due to neuroinflammatory diseases of the brain, environmental factors and even an individual’s lifestyle.

Gender may affect pain experience

A study by H.H. Doyle and other researchers from Georgia State University revealed the difference in brain activity when males and females experience pain. This study was conducted earlier this year.

Researchers found that the brain’s resident immune cells, known as microglia, are more active in regions involved in pain processing for females as compared to males. The prevalence of chronic and inflammatory pain conditions is higher in women, and women usually require almost twice the amount of morphine required by men to produce pain relief.

This study suggests that microglia may be an important drug target for the treatment of pain, particularly in women.

BMI contributes to pain threshold

Gender is not the only factor that differentiates the pain experience. In a study published earlier this year, it was found that the role of body mass index (BMI) and distribution of body fat influenced sensory detection and pain sensitivity.

The study was conducted by O. A. Tashani, from the School of Clinical and Applied Sciences in Leeds Beckett University, together with three other researchers. It consisted of over 70 participants who were categorised into groups based on their BMI (normal, overweight and obese).

Results showed that the mean pressure pain threshold of the obese group was significantly lower than normal groups. Pain responses also varied according to subcutaneous body fat at different body sites.

Parents’ behavior affect pain response in children

Another interesting finding is from a study that revealed how a child’s experience and response to pain can vary based on his parents’ behaviour. This study was conducted by Christine T. Chambers from the Centre for Community Child Health Research, together with several other researchers, and was published in 2002.

A significant correlation was observed between a child’s pain and distress with certain types of maternal behaviours. Girls whose mothers interacted with them in ways that promoted the pain – such as reassurance followed by apologies, empathy and giving control - reported higher levels of pain intensity as opposed to those whose mothers reacted spontaneously.

However, the pain intensity level was the lowest in the group of girls whose mothers interacted with them in a pain-reducing manner – such as nonprocedural talk, humour and commands to use coping strategies. Interestingly, the maternal interaction type did not have an equally significant effect on the pain intensity for boys.

Pain and empathy

In a study published in 2015, social neuroscientist Claus Lamm, along with colleagues at the University of Vienna, asked participants to rate the extent of pain felt from small electric shocks. They were then asked to estimate the pain they experienced by someone in an adjoining room who was given the same type of shocks.

Participants who received the placebo pill reported less pain and also rated others’ pain as lower, compared to participants who were not given the pill. The experiment was repeated, but some participants were given naltrexone, a drug which prevents the function of opioid painkillers by blocking the opioid pathways in the brain.

The result was diminished pain and empathy in those participants. Findings from the study suggest that pain empathy is grounded in neural responses and neurotransmitter activity related to first-hand pain.

A sound understanding of the different factors that influence the human pain experience is crucial to determine the appropriate and most effective intervention for pain management. It is hoped that future studies can benefit by extrapolating results from previous research and aim to explore further the different variations involved in pain mechanisms and individual experience. MIMS

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