Massage therapists are no strangers to pain; in fact, pain is one of the main reasons clients seek out massage therapy. New research shows human brains process acute pan differently, depending on whether or not chronic pain is present to begin with.

Researchers from Northwestern University Feinberg School of Medicine in Chicago used functional magnetic resonance imaging to compare brain activity in response to acute noxious thermal stimuli in healthy control subjects and in patients with chronic back pain.

The researchers found pain perception and related brain activation patterns were nearly identical in the two groups; however, there was one profound difference in the activity of a specific part of the brain called the nucleus accumbens.

The researchers discovered that phasic nucleus accumbens activity at the beginning of painful stimuli predicted pain perception and at termination of painful stimuli predicted reward (pain relief) in the healthy group.

In the subjects with chronic back pain, nucleus accumbens activity correlated with different neuronal circuitry than the controls, and its phasic activity at the end of the stimulus was in the opposite polarity than the healthy subjects, suggesting that the acute pain relieved the ongoing back pain.

“These findings point to a potential dysfunctional associative learning process in chronic pain patients,” said lead researcher Dr. A. Vania Apkarian.