We know what pain feels like, and know that it’s caused when something goes wrong – but how does it actually work?
First, it’s helpful to understand that there’s three different types of pain: nociceptive pain, neuropathic pain, and psychogenic pain.
Nociceptive pain is the result of a stimulus being sent from part of your body (as a result of pressure, damage etc) to your brain. In basic terms: stimulus occurs (say, you cutting yourself or pulling a muscle), nerve endings register that stimulus, the nerve sends a signal to the central nervous system, where it’s sent to your thalamus (the sorting station that makes sure signals get to the right part of the brain). Signals are sent to the somatosensory cortex (responsible for physical sensation), the frontal cortex (in charge of thinking), and the limbic system (linked to emotions). As a result: you feel the pain, are triggered to think about the cause, and react emotionally (frustration, fear) – a system designed to make you do something to rectify the situation.
Different types of nociceptive pain are carried by different nerve fibers; this why you experience different types of pain (dull, sharp, etc). Sharp, pricking pain is carried by A-delta fibers while dull throbbing pain travels via C fibres. A-delta fibers conduct signals faster than C fibers as they are larger and are coated in myelin, which acts an electrical insulator; the sharp pain you feel when you cut yourself is A-delta fibers, the dull ache which follows is C fibers.
Neuropathic pain is caused by issues with the system that carries and interprets pain signals; these mixed signals cause you to feel pain from stimuli that are not normally painful (for example, the sheets on your bed touching the affected area), or experience extreme pain from stimuli that should only register as mildly painful. Possible causes include damage to nerve endings, viruses (shingles often cause neuropathic pain), and the brain being constantly bombarded by C-fiber pain signals (pain signals get amplified; eg, you may feel a cut more intensely when you’re suffering from period pain).
Psychogenic pain is pain that is worsened or caused by psychological factors; this doesn’t mean that the pain isn’t real, it’s simply complicated by the emotional and mental processes happening in the brain.
These types of pain can then be sub-classified as acute and chronic; acute pain is short-lived, and chronic pain is persistent. Sometimes chronic pain is caused by ongoing tissue damage (for example, arthritis); sometimes no physical cause can be determined, sometimes pain lingers long after an injury is healed (eg nerves regrow, but don’t function properly any more).
Pain is incredibly subjective, and it’s important to understand what kind of pain you’re experiencing in order to treat the cause, rather than just the symptoms. Chiropractic can be beneficial in this situation, as chiropractors specialise in the spinal cord and central nervous system.