Acute Pain vs. Chronic Pain: What the Brain’s Volume Knob Is Doing

It's best to nip pain in the bud before it becomes chronic

Why does pain sometimes fade as expected, and other times stick around long after the original injury has healed?

A recent article in Medscape Medical News highlights a new study that sheds light on this question. Researchers found that during acute pain, certain neurons in the brainstem actually turn down their activity, as if the brain has a built-in volume control. But in chronic pain, that “volume knob” may stop working. The result? Pain that no longer serves a protective purpose and becomes part of daily life.

A Built-in Brake for Acute Pain

The study, published in Science Advances, focused on neurons in the medullary dorsal horn, which is part of the brainstem that relays pain signals to other parts of the brain. When mice were exposed to an acute pain stimulus (ultraviolet light), these neurons became less excitable. It’s as if the nervous system, faced with intense input, applied a brake to prevent overload.

This runs counter to the long-held assumption that more pain always means more nerve activity. Instead, it suggests the nervous system can modulate pain from within, adjusting how much input gets through, not just based on intensity but on context and need.

As the researchers put it: during acute pain, the nervous system may engage protective mechanisms to dampen the signal. But when pain becomes chronic, that protective mechanism may disappear.

What Happens in Chronic Pain

In the same study, when mice experienced longer-term pain (through a simulated migraine-like model), the natural braking system was no longer present. The pain-related neurons did not show the same dampening effect observed during acute pain. Instead of calming down, they remained active, as if the system had forgotten to turn the volume down.

This is similar to how our senses usually adapt. When you walk into a room with a strong odor, the smell may hit you hard at first, but quickly your nervous system adjusts and the intensity fades. Acute pain should work in a similar way — a sharp signal that quiets once the immediate threat is over. In chronic pain, that fading doesn’t happen. The system keeps sending alerts even when nothing new is occurring.

This breakdown of internal modulation may help explain why chronic pain feels so relentless. It’s not just tissue damage. It may also be that the nervous system has lost part of its ability to regulate the experience.

What This Means for Rolfing & Therapeutic Massage

For those of us working hands-on with people in pain, this research aligns with what we often see: pain is not just about structure. It’s about input, interpretation, and modulation.

In my practice, I often work with people whose pain persists even though nothing looks clearly wrong on imaging. That doesn’t mean the pain isn’t real. It may mean the nervous system is amplifying signals, or failing to turn them down, even when there’s no longer a major injury.

Through decompression, improved nerve glide, and calming the body’s input systems, therapeutic bodywork may help some people regain a sense of modulation.

Acute vs. Chronic Pain: Not Always a Clean Line

It’s also worth remembering that the shift from acute to chronic pain isn’t a simple on-off switch. There may be early signs: increasing sensitivity, pain that spreads beyond the original site, or discomfort that lingers longer than expected. These patterns suggest that the nervous system might be starting to adapt in less helpful ways.

Intervening at that point — before the system gets locked into a chronic pain loop — can make a big difference. That’s part of why structural integration, gentle nerve work, and movement-based approaches may feel so different from simply working on sore muscles.

Closing Thoughts on Pain

This research is early-stage and based on animal models, but it offers a useful metaphor. Pain may not just be a signal coming in; it may also depend on how the system filters, amplifies, or dampens that signal. If the brain’s volume knob is broken, no amount of rest or medication may fully solve the problem on its own.

That’s where supportive, hands-on work can help. Skilled, therapeutic bodywork can help your nervous system recalibrate.

Book a consultation or session if you'd like to understand more about your issues with chronic or acute pain.

Read more about pain science here.