When we are in pain, it's hard to think about anything else. The pain takes over; we turn inward. Daily tasks such as getting dressed or making dinner take a great deal more effort. It's hard to stay focused and proceed from one step to the next.
What happens then to someone with chronic pain? Does the continual presence of pain change the brain both physiological and anatomically? If so, are these changes reversible? A recent article in the Journal of Neuroscience suggests that the answer to both of these questions may be yes.
In this study, eighteen adult patients with chronic low back pain were studied. The investigators performed functional MRIs on the patients before and six months after they received treatment for their pain. During this same period, brain scans were also taken from sixteen healthy, control participants. The investigators found several areas of the cerebral cortex that were thinner in patients than in controls, including a region in the frontal cortex called the dorsolateral prefrontal cortex (DLPFC). This area may play a role both in pain modulation and in the performance of attention-demanding, cognitive tasks.
During the brain scans, participants performed a cognitive task which consisted of distinguishing a visual target from other characters. Although patients and controls performed the task equally well, the patients showed more activation of several brain regions including the DLPFC. Since pain is an attention -demanding process, the patients may have had to exert extra effort to stay focused on the task, and this effort may have been reflected in increased brain activity.
After treatment (spinal surgery or joint block), the majority of patients experienced pain relief. Strikingly, the thickness of the DLPFC increased in every patients who reported an improvement in his or her pain, while the DLPFC did not show an increase in thickness in two out of the three patients who did not respond to treatment. Patients whose pain had subsided also activated the DPLFC to a smaller extent when performing the cognitive task. Indeed, activation of this area now resembled that of control subjects.
When an individual recovers from chronic pain, it's not only the body that recovers. The brain recovers too.