
2. How do we perceive pain?
Have you ever instinctively withdrawn your hand after touching a boiling pot by accident? Pain sensations start with the activation of pain receptors—or nociceptors—in your hand. The information is conducted to the spinal cord, before entering higher brain areas for the perception of pain. However, perception of pain is a subjective experience, and some people experience pain more or less severely than others. Why?
The gate control theory of pain, as proposed by Canadian researcher Ronald Melzack, suggests that pain signals that enter the spinal cord can be modified—amplified, diminished or completely blocked—before they enter the brain. Supporting this theory are the many accounts of how people injured on battlefields or while playing sports do not experience pain until much later.