When we talk about pain, we usually focus on the physical area of the body where it hurts. We use metaphors to say it is “stabbing” or similes to talk about pain feeling like a “vice grip.” But what if pain really was all in your head? It turns out that technically that is 100% accurate. The brain is the mechanism that processes all sensation in the body. When a muscle is sore, it’s sore because nerves send a signal that your brain processes as pain.
But a brain in pain does even more than that: it remembers it and responds differently to words and situations the longer it is processing pain.
Thomas Nevian and his colleague Mirko Santello from the department of physiology at the University of Bern have found a mechanism in the brain of laboratory mice that actually remembers pain and contributes to it becoming chronic. When laboratory mice experienced long-term (chronic) pain, the neurons in a brain region called Gyrus Cinguli changed so that traces of that memory became “etched” in those neurons. Once changed, the researchers found that this brain memory (a “memory trace”) is irreversible.
Nevian and Santello found that the Gyrus Cinguli was more receptive to electrical impulses signaling pain in the brain due to a specific ion channel that was not well-regulated. This ion channel basically determines the electrical conductivity in the cell membrane. Think of the cell membrane as a fortified wall keeping the enemy (an electrical pain impulse) at bay. If there is a hole in the wall (a down ion channel), then the enemy (pain) not only streams through that hole but also remembers where it is.
The researchers then tried to figure out a way to boost the activity of that ion channel – to plug the hole in the cell membrane that allowed electrical pain impulses to stream through unimpeded. They found that the neuromodulator serotonin (the “feel good” hormone in the brain) reduced pain in the lab mice. This offers strong support for the use of serotonin-boosting anti-depressants and also gives some insight into how they work to fight chronic pain. Although this is promising research, both scientists caution that new treatments may be a long way off: “