How does pain happen?

Author: SCIRE Community Team | Reviewer: Patricia Mills | Published: 12 April 2017 | Updated: 18 October 2017, 10 October 2024

Pain happens differently depending on where it comes from in the body.

Pathway of pain signals from the body tissues.⁴

Nociceptors are special sensors in the body tissues (like the skin and muscles) that detect possible damage to the body.

When nociceptors are activated, they send signals through the nerves and spinal cord to the brain.

In the brain, these signals are recognized and interpreted together with other nerve signals from the brain and body, resulting in the experience of pain.

Pathway of pain signals from the nerves.⁵

Pain from the nerves is different. When the nerves themselves are injured, there are no nociceptors involved. Instead, the signals about potential damage come from somewhere along the pathway of nerves from the body to brain.

Damage to the nerves (including the spinal cord) can cause signals related to pain to be sent inappropriately, resulting in many of the unique features of neuropathic pain.

The pain pathway is complex. Pain signals are not static but can be turned up or down (or modulated) by other nerve signals from both the body and brain. In other words, the pain experience can change depending on other factors, such as worsening during a urinary tract infection, or improving with distraction during enjoyable activities.

Nerve signals from the body, such as those involved in touch, can alter pain signals. This is like how rubbing the skin over a sore area of the body makes it feel better. Nerve signals from the brain, like those involved in emotions and thoughts, can also affect feelings of pain. For example, fear can make pain worse but feeling calm or even distracted can reduce pain.

This happens because of the many different nerve connections involved in the experience of pain.