What is Pain?

Pain is, by and large, a pretty complex topic and one that is still being extensively researched. Pain is experienced differently by everyone because ultimately it is the interpretation of sensory stimuli. The brain contains approximately 86 billion neurons, meaning the possible combination of connections between these neurons is almost infinite. This makes every person’s experience unique to them. This is part of the reason that pain is so incredibly hard to quantify because the experience of it is so subjective.

What exactly, from a neurobiological perspective then, is pain?

Well, pain is three entirely different things. First, there is the pain that is an early-warning physiological protective system, essential to detect and minimize contact with damaging or noxious stimuli. This is the pain we feel when touching something too hot, cold, or sharp for example. Because this pain is concerned with the sensing of noxious stimuli, it is called nociceptive pain. The neurobiological apparatus that generates nociceptive pain evolved from the capacity of even the most primitive of nervous systems to signal impending or actual tissue damage from environmental stimuli. Its protective role demands immediate attention and action, which occur by virtue of the withdrawal reflex it activates, the intrinsic unpleasantness of the sensation elicited, and the emotional anguish it engages. Nociceptive pain presents itself as something to avoid now, and when engaged, the system overrules most other neural functions.

flexor withdrawal reflex docstoc

One of the most common mistakes held by practitioners who deal with people in pain is that nociception, always results in the sensation of pain. Deal with the nociception and you’ll get rid of the pain. While this holds some truth, it’s certainly not the whole story. In fact, pain researchers have shown that nociception is neither sufficient nor necessary for pain on its own.

The second kind of pain is also adaptive and protective. By heightening sensory sensitivity after unavoidable tissue damage, this pain assists in the healing of the injured body part by creating a situation that discourages physical contact and movement. Pain hypersensitivity, or tenderness, reduces further risk of damage and promotes recovery, as after a surgical wound or in an inflamed joint, where normally innocuous stimuli now elicit pain. This pain is caused by activation of the immune system by tissue injury or infection, and is therefore called inflammatory pain; indeed, pain is one of the cardinal features of inflammation. While this pain is adaptive, it still needs to be reduced in patients with ongoing inflammation, as with rheumatoid arthritis or in cases of severe or extensive injury.

Finally, there is the pain that is not protective, but maladaptive, resulting from abnormal functioning of the nervous system. This pathological pain, which is not a symptom of some disorder but rather a disease state of the nervous system, can occur after damage to the nervous system (neuropathic pain), but also in conditions in which there is no such damage or inflammation (dysfunctional pain). Conditions that evoke dysfunctional pain include fibromyalgia, irritable bowel syndrome, tension type headache, temporomandibular joint disease, interstitial cystitis, and other syndromes in which there exists substantial pain but no noxious stimulus and no, or minimal, peripheral inflammatory pathology. The clinical pain syndrome with the greatest unmet need, pathological pain is largely the consequence of amplified sensory signals in the central nervous system and is a low-threshold pain. By analogy, if pain were a fire alarm, the nociceptive type would be activated appropriately only by the presence of intense heat, the inflammatory pain would be activated by warm temperatures, and pathological pain would be a false alarm caused by malfunction of the system itself. The net effect in all three cases is the sensation we call pain.


One thing that is true across the entire human race is that pain is a conscious experience. There can be an abundance of noxious stimuli within the system with no pain, but there can be no pain without conscious awareness.

When someone wakes up with pain that wasn’t there the day before, they naturally look for rational reasons as to ‘what they did’ to create it. They don’t remember any impact, a particular injury or action so assume they must have slept funny! Truth be told, the day pain decides to make itself present may have more to do with what you haven’t dealt with, than anything you’ve done.

If we fall over and hurt ourselves, pain is an acceptable outcome of apparent damage to the tissues. “My knee hurts because I tripped and slammed it onto the pavement.” The wound heals, your movement gradually returns to normal and that’s the end of the story.

Pain that seemingly comes out of nowhere could possibly be linked to an old injury but has never actually cleared, or it recurs and perhaps has even become chronic and this type of pain is not so easily rationalised.

At AMN Academy, we currently believe that any pain complaint not related to impact injury or tissue damage can be classified as an effect of altered homeostasis. It is the conscious perception of sub-conscious, autonomic imbalances.

Just as the proliferation of illness or disease can be gradual and develop in stages; strange, unexplained and often persistent pain complaints are the culmination of several systems miss-communicating.

This kind of faulty communication can occur between any or all of the layers of the somatic nervous system (movement system), the visuomotor and vestibular (balance) systems, the enteric nervous system (gut and other viscera), endocrine system (hormones), immune (host defence system) and limbic system (emotional brain).

A pain complaint that becomes a pain condition over say, a decade, will most likely not be mediated by the same mechanisms that it was initially. Let’s take a pain issue that arises from a particular emotional stress. Maybe an area of the body that was previously injured begins to hurt in relation to a negative emotional experience. You can deal with the emotional issue and still the pain remains. Equally, you could correct muscle imbalances until your blue in the face, but until the original problem is collapsed into consciousness and released, you may have absolutely no effect on the person’s painful shoulder!

This is because no system in the entire brain and body works in isolation. Indeed for pain to be experienced in a body area due to emotional stress there are links, connections and projections within the brain that couple our organs, glands, thoughts, emotions and body tissues and we can never hope to understand how all of this works precisely.

So if the practitioner can’t really know precisely what’s going on in every one of these systems simultaneously at a given moment in time, who is qualified to define what is involved in a particular presentation?

To put it simply, we ask the client’s brain to show us.

The patient or client’s brain is the most qualified to show which of the multitude of possibilities is involved in the pain issue; it is also the best equipped to positively influence the problem. The role of the practitioner is to understand how to communicate with the nervous system in the first place and then to facilitate the corrective process.

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