How does your brain produce pain?

For a long time, it was believed that pain functioned like a simple electrical wire: you hurt your foot, a signal travels to the brain, and you feel pain. But modern science reveals a much more fascinating reality—and one that is much more encouraging for people living with chronic pain.

Your brain is not simply a passive receiver of pain signals. It decides whether or not you will feel pain, based on a multitude of factors. This understanding changes everything in the approach to persistent pain.

Nociception: It's not yet pain

The detection system

The word "nociception" comes from the Latin nocere, which means "to harm." It refers to all the mechanisms by which your body detects potentially dangerous stimuli. But—and this is crucial— nociception is not pain.

Throughout your body, you have specialized sensors called nociceptors. These are the free endings of certain nerve fibers, capable of detecting three types of stimuli:

• Mechanical: excessive pressure, stretching
• Thermal: extreme heat or cold
• Chemicals: substances linked to inflammation or injury

When these sensors detect something potentially threatening, they send a signal to your spinal cord, then to your brain.

From signal to brain: three stages

The stimulus (pressure, heat, etc.) is transformed into an electrical signal by nociceptors.

The signal travels along the nerve fibers to the spinal cord, where it is relayed to different regions of the brain.

This is where everything happens. Your brain analyzes the signal it receives based on the overall context and decides: "Does this body need protection?" If the answer is yes, you will feel pain. If the answer is no, the signal will be attenuated or blocked.

Why pain does not always reflect the condition of your tissues

Surprising discoveries

Scientific research has demonstrated several facts that may seem counterintuitive:

In the laboratory, nociceptive fibers are activated at 42°C, but pain is generally only felt at 44°C, sometimes even 52°C. The brain "filters" these signals.

A hot pin generates 20 times more nerve impulses than a pin at room temperature, but both can produce the same sensation of pain.

A stimulus of 45°C on 1 mm of skin causes a stinging pain. On 20 mm? A pleasant sensation of warmth. Bigger does not equal more painful.

During a continuous painful stimulus lasting 15 seconds, nociceptors are very active at first, then their activity rapidly decreases—but the pain continues.

The key message

This is why two people with the same injury can have completely different experiences of pain. It is also why you can be in pain without any visible injury—and have an injury without proportional pain.

The brain: conductor of pain

The neuromatrix

There is no single "pain center" in your brain. Instead, pain is produced by a complex network of brain regions working together—known as the neuromatrix.

This network includes areas responsible for:

• Physical sensation (somatosensory cortex)
• Emotions (limbic system, amygdala)
• Memories (hippocampus)
• Decision making (prefrontal cortex)
• Movement (motor cortex)

All these regions communicate with each other to assess whether protection is needed. This is why pain always has an emotional component—the emotional areas are an integral part of the pain network.

The DIM/SIM model

A simple way to understand how your brain decides to produce pain is the DIM/SIM model:

When danger signals exceed safety signals (DIM > SIM), your brain produces pain. When safety signals dominate (SIM > DIM), pain decreases.

These signals can be:

• Biological: inflammation, fatigue, poor sleep
• Psychological: fear, stress, negative beliefs
• Social: conflicts, isolation, insecurity at work

Downward modulation: The volume of your alarm system

Your brain can increase or decrease pain

Your brain has powerful mechanisms for modulating—increasing or decreasing—pain signals. This is called descending modulation.

In certain circumstances, your brain can block pain signals by releasing natural opioids (endorphins). This is why a soldier wounded in combat may feel no pain until he is safe—his brain judges that immediate survival is more important than protecting the wound.

Conversely, your brain can also amplify pain signals when it perceives a significant threat. It's like turning up the volume on your alarm system.

The gate of pain

At the level of your spinal cord, there is a "gate" that pain signals must pass through to reach the brain. This gate can be more or less open depending on:

• Signals from the brain (downward modulation)
• Other sensations originating from the same area (which is why rubbing a painful area can provide relief)
• The overall condition of your nervous system

Awareness: When the system becomes too reactive

An incorrectly calibrated alarm system

When your nervous system is exposed to pain for a prolonged period of time, it can become more sensitive—a phenomenon known as sensitization. Researchers consider it the "jewel of modern pain science": it is the tendency of the nervous system to get stuck in a rut and overreact to stimuli — an alarm system that goes off too easily. It's as if the volume of your alarm system has been permanently turned up.

Peripheral awareness

At the tissue level, nociceptors may become more reactive:

• They activate more easily (for less intense stimuli).
• They remain activated for longer
• They can even generate signals spontaneously, without any stimulus.

This often explainshyperalgesia (excessive pain in response to a normally mildly painful stimulus) andallodynia (pain in response to a normally non-painful stimulus, such as a simple touch).

Central awareness

Signal processing can also be amplified in your spinal cord and brain:

• The "doors" of the spinal cord open more easily
• Downward inhibition decreases (less restraint)
• Top-down facilitation increases (more amplification)
• Brain regions become more responsive

What is important to understand: central sensitization can be biological, psychological, or social in origin. Chronic stress, catastrophic thinking, social isolation—all of these can contribute to sensitizing your nervous system.

Neuroplasticity: The Good News

Your brain can change

If your nervous system has "learned" to be more sensitive, the good news is that it can also "unlearn." This is the principle of neuroplasticity —your brain's ability to reconfigure itself based on your experiences.

The same mechanisms that have made your system more sensitive can work in the opposite direction. By changing the signals you send to your brain—through movement, education, and stress management—you can gradually "recalibrate" your alarm system.

How to promote positive neuroplasticity

Gradually reintroducing movements that you had been avoiding shows your brain that these movements are safe. This is one of the fundamental principles of physical therapy for chronic pain.

Understanding how your pain works reduces the perception of threat—which directly reduces "DIM" and can decrease pain.

Chronic stress sensitizes your nervous system. Stress management strategies (breathing, relaxation, physical activity) can help to "desensitize" it.

Quality sleep is essential for regulating your nervous system. Sleep disorders amplify pain, creating a vicious cycle.

What this means for you

The pain is always real

Whether your pain is caused by tissue damage, heightened sensitivity in your nervous system, or a combination of both—it is always real. Neuroscience does not say that your pain is "all in your head" in a pejorative sense. It says that your brain is involved in every experience of pain—and that's good news, because it means you have levers to influence it.

You have power

Understanding the neuroscience of pain empowers you:

• You are not doomed to suffer because your tissues are "damaged."
• Your nervous system can recalibrate itself
• Factors that you can control (movement, thoughts, stress, sleep) directly influence your pain.

A comprehensive approach is key

Because pain involves biological, psychological, and social factors, an approach that addresses all these aspects is more effective than one that focuses solely on the tissues. That is why modern physical therapy for chronic pain includes education, graded movement, and attention to psychosocial factors.

Key takeaways

• Nociception is not pain —danger signals must be evaluated by your brain before they become pain.

• Your brain decides how much pain you feel —based on the balance between danger signals (DIM) and safety signals (SIM).

• Downward modulation can increase or decrease your pain depending on the context.

• Awareness can make your system more responsive, but it is reversible.

• Neuroplasticity allows your brain to reconfigure itself—you can influence your pain.

The science of pain is liberating: it shows us that even when tissues are healed, we are not condemned to pain. With the right understanding and strategies, change is possible.

Additional resources

• Understanding Chronic Pain: A Comprehensive Guide
• Acute pain vs. chronic pain
• The psychology of pain
• Pain management strategies
• Neuropathic pain