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Nocioception | Pain

Writer: J FelixJ Felix

Updated: Nov 19, 2024

Nociception: Physiological pain component, which consists of the processes of transduction, transmission, and modulation of neural signals generated in response to a harmful external stimulus.


I was benching 225 and feeling strong. I added a dime on each side and pressed a set of 8. I added another 10 and repped 7. I asked my spotter to strip off the 10s and add quarters. I was repping 6 at 275. "Let's add three 45s on each side," I said. I started my first rep. I felt strong. As I lifted the bar off my chest on my second set, I heard a pop and lost all my strength. My spotter grabbed the bar. I felt a terrible pain in my right shoulder. I immediately defaulted to training and breathed into the pain. I sat up. My right arm hung limp. Something was terribly wrong.


The pain was exquisite. I kept breathing into it and stayed with it. I drove to intensive care and was told I might have ruptured something. They asked me if I needed anything for the pain. I may have taken Motrin, but relied more on the breath.


The pain hurt, but the self-pity was worse. So, I dropped it like I dropped the weights.


No self, no suffering. Painful sensations may arise, but absent ego, there is no self to suffer. Pain may be inevitable, but suffering is not.


"At its core, pain is just something that hurts or makes you say ouch," says Karen Davis, a senior scientist at the Krembil Brain Institute in Toronto. "Everything else is the outcome of the pain, how it then impacts your emotions, your feelings, your behaviors."


The ouch-ness of pain begins when something activates special nerve endings called nociceptors. "Once they are activated, they trigger a whole cascade of events with kind of a representation of that signal going through your nerves and into your spinal cord and then all the way up to your brain," Davis says.


The vagus nerve plays a key role in the processing of pain. Its job is to send crucial electrical messages back and forth between the brain and the body. The vagus nerve runs from the brainstem at the bottom of the brain along the spinal cord to the colon, branching out on the way through the neck, chest and abdomen. Pain signals travel up and down this superhighway and interact with many different brain areas, including those involved in physical sensation, thinking and emotion.


"There's quite a pattern of activity that permeates through the brain that leads to all the complexities of what we feel associated with that initial hurt," Davis says.


Robyn Crook, a biologist and brain researcher at San Francisco State University, explains that the most obvious evolutionary reason for pain is to prevent or minimize damage to the body. Touch a hot stove and pain tells you to move your hand away. Fast.

But evolution doesn't stop there.


"In some animals with more complex brains there's also an emotional or a suffering component to the experience," she says. And there must be a reason for that, Crook says. One possibility, she says, involves memory. "Having that emotional component linked to the sensory experience really is a great enhancer of memory," she says. "And so humans, for example, can remember a single painful experience sometimes for their entire lives."


I haven't gone too heavy since that experience. Lesson learned.


And there may be another reason that people and other highly social animals have brains that connect pain and emotion, Crook says. "Experiencing pain yourself produces empathy for other group members or other family members that are in pain," she says. As a result, if one of them is injured "you will offer help to them because of the empathetic response or the emotional response to pain." That response has obvious benefits for animals that live in groups, Crooks says.


Most of us will experience physical pain at some point in our lives. It can be an excellent teacher.


After my surgery, the doctor prescribed narcotics for the pain. I am grateful for the pain-killers, but took them sparingly- only for 2 or 3 nights before bed when the pain was most intense. I used meditation throughout the day, post recovery, and during physical therapy.


I trusted that my meditation techniques could be an alternative to drugs. I could experience sensations as sensations. I could separate the pain from the self and relinquish the aversion we offer associate with pain. I experienced throbbing as throbbing, stinging as stinging, heat as heat- relinquishing evaluative judgments as "bad."


Meditation has been used to manage pain for millennia. A new study, published in Biological Psychology, found meditation to engage distinct brain mechanisms to reduce pain compared to those in the placebo group. The study found that mindfulness meditation produced significant reductions in pain intensity and perceived pain unpleasantness. Researchers also found reduced brain activity patterns associated with pain and negative emotions. There was no such effect seen in the brain scans of those given the placebo.


I discontinued the opioids after a few days. The pain was exquisite. I could keep my attention on the pain easily and effortlessly. It was a strong object to rest concentration on.


I knew there were 2 types of pain- primary and secondary. The primary pain was raw. When I let go of loaded words like pain, however, I could explore it objectively- the throbbing, the burning, the intensity.


The emotional pain is secondary and can amplify the pain. When we evaluate pain as "bad," we engage regions of the brain that associate with pain processing. We can also provoke rumination and fearfully focus on the pain. And when pain doesn't go away, it can cause disabling changes in the brain.


"Pain is a danger signal," Crooks says. "But once pain becomes chronic, once it's ongoing, these pain signals no longer serve a useful purpose." Over time, these signals can lead to problems like depression, anxiety, and stress- which make the pain even worse.


In a recent study, researchers found reduced grey matter volume in the pain-processing areas and regions responsible for the inhibition of pain in patients who suffered fibromyalgia, a disorder characterized by widespread musculoskeletal pain. Altered signal transmission was observed in the thalamus of patients, indicating changed pain signaling. The thalamus plays an important node in neuronal pain processing. “This indicates that changes in the brain may not be permanent, but that they can be influenced; in other words they might be reversible, for example through an active everyday life,” concluded one of the researchers.


The dorsal anterior cingulate cortex is another key region that influences pain perception and processing with direct influences on autonomic function. In another study, researchers focused ultrasound waves on the dorsal anterior cingulate cortex and found that patients reported feeling less pain. Physiologically, the heart did not respond as strongly to pain and blood pressure remained unchanged (Strouhman, 2024).


Physical pressure on cells can reduce pain signals. If I bump my head, for example, I might rub it intuitively to lessen the pain. Interestingly, researchers found that excessive cholesterol clumps in cell membranes can interfere with that process. Cell membrane lipids, or fats, help send an electrical pulse into cells after experiencing pressure and force. The cell membrane isn't simply a fatty sac, though. Rather, it's a sophisticated collection of sensors, pores, channels, receptors, and cholesterol clumps held in place by precisely arranged fat molecules. Membrane lipids sense tension and engage mechanosensors. A mechanical force-sensing enzyme called PLD2 activates a pain-relief-providing potassium channel called TREK-1 (Peterson et al., 2024).


Research illuminates the path that pain signals take from an injury site to the brain. Excess cholesterol in cell membranes, however, may interfere with pain control. This could be one reason why clinicians see more chronic pain symptoms in people with high cholesterol.


Pain travels through the nervous system as electrical signals. When an electrical signal reaches the end of a nerve cell, it is converted into a biochemical signal in the form of calcium. An increase in calcium triggers the release of signaling molecules called neurotransmitters. Neurotransmitters are received by the next nerve cell which converts the signal back into electricity.


 In the calcium channel there are four so-called voltage sensors that detect electrical nerve impulses. When the voltage is high enough, the voltage sensors move and make the channel open, so that calcium can flow through.


These channels are like gates that sense electrical signals and then open to allow calcium to flow into the nerve cell. A specific type of calcium channel called CaV2.2 is involved in the transmission of pain signals. These channels are more active during chronic pain. They are located at the ends of sensory nerve cells (Nilsson et al., 2024).


To feel pain, first, the injury must be sensed. Second, that injury message must convert to a signal that can travel rapidly through the body and be interpreted by the brain. The lipid structure appears to sense the force and convert it into a signal. The signal can then help activate the body's own pain-relieving responses—so long as there's no interference—lessening the pain's severity.


Changes in brain structure correlated with patients’ pain perception and that behavior could be influenced, suggesting potential reversibility. With mind, we can reduce synchronization between brain areas involved in introspection, self-awareness and emotional regulation.


Meditation has helped me gain some control over the way the brain processes pain signals. By letting go of storylines, slowing the breathing and relaxing the muscles, we can be with it fully. These techniques can be powerful compliments to conventional treatments.






 
 
 

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