New Hope for Sufferers of Chronic Pain
Pain is one of several sensory systems that keep us apprised of the status of our bodies. As we hurry through our daily lives, we usually view pain at the very least as an inconvenience, if not a major disruption. It’s fortunate that we have our pain sensors – they provide a valuable warning to us that we need to stop and take care of ourselves. Pain has considerable survival value, but when an injury has healed and the pain continues unabated, or when pain seems to have no obvious connection to any injury, it no longer serves a useful purpose. Pain of this type is referred to as chronic pain, and once you have fallen under its sway, it may be very difficult to escape.
The Challenge of Pain Management The management of chronic pain has always been a medical challenge. Treatment often involves increasing doses of a variety of medications in an effort to gain a measure of relief. In some instances, the pain is significantly reduced with the use of medication, but when the drugs are removed the pain returns, and so the meds become a more or less permanent fixture of life, often resulting in drug dependence or even addiction. In other cases even heavy use of medication provides the sufferer little or no relief; the brain simply adjusts to the presence of the medications and demands more, while the pain continues
Real-time fMRI applied to pain management
Modern views conceptualize pain as a brain-based phenomenon. Advances in neuroscience have allowed us to explore how the varieties of pain experience we observe are mediated by the complex relationships between the mind, brain, and body. We have learned that far from activating a single “pain” center in the brain, pain results in widespread activation of multiple cortical and subcortical regions involved in many functions including primary and secondary somatosensory areas (SI, SII), primary motor (MI) and premotor cortices (PMC), supplementary motor area (SMA), basal ganglia, parietal and insular cortices, periaqueductal gray (PAG), rostral ventromedial medulla, hippocampus, amygdala, parahippocampus, anterior cingulate cortex (ACC), and prefrontal cortex (PFC).
Pain experience can be influenced by many cognitive, emotional, and other factors affecting brain function. Indeed, evidence suggests that many of these areas participate in a pain modulatory pathway and can have a significant effect on pain experience. The brain’s central role in pain experience is underscored by the growing appreciation that chronic pain involves dysregulation of central pain modulatory systems. A number of studies have revealed that the brains of patients with chronic pain are functionally and structurally altered compared to healthy controls. Alterations in functional connectivity between brain regions have been found in various chronic pain conditions
Control Over Brain Activation and Pain Learned by Using Real-Time Functional MRI
If an individual can learn to directly control activation of localized regions within the brain, this approach might provide control over the neurophysiological mechanisms that mediate behavior and cognition and could potentially provide a different route for treating disease. Control over the endogenous pain modulatory system is a particularly important target because it could enable a unique mechanism for clinical control over pain. Here, we found that by using real-time functional MRI (rtfMRI) to guide training, subjects were able to learn to control activation in the rostral anterior cingulate cortex (rACC), a region putatively involved in pain perception and regulation. When subjects deliberately induced increases or decreases in rACC fMRI activation, there was a corresponding change in the perception of pain caused by an applied noxious thermal stimulus. Control experiments demonstrated that this effect was not observed after similar training conducted without rtfMRI information, or using rtfMRI information derived from a different brain region, or sham rtfMRI information derived previously from a different subject. Chronic pain patients were also trained to control activation in rACC and reported decreases in the ongoing level of chronic pain after training. These findings show that individuals can gain voluntary control over activation in a specific brain region given appropriate training, that voluntary control over activation in rACC leads to control over pain perception, and that these effects were powerful enough to impact severe, chronic clinical pain.