Chronic pain is one of the most prevalent health problems in our modern world, with millions of people debilitated by conditions such as back pain, headache and arthritis. To address this growing problem, many people are turning to mind-body therapies, including meditation, yoga and cognitive behavioural therapy. This article will review the neural mechanisms underlying the modulation of pain by cognitive and emotional states - important components of mind-body therapies. It will also examine the accumulating evidence that chronic pain itself alters brain circuitry, including that involved in endogenous pain control, suggesting that controlling pain becomes increasingly difficult as pain becomes chronic.

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Cognitive and emotional control of pain and its disruption in chronic pain

The effect of pain on cognitive function: a review of clinical and preclinical research.

Towards a theory of chronic pain

We review recent advances in brain imaging in humans, concentrating on advances in our understanding of the human brain in clinical chronic pain. Understanding regarding anatomical and functional reorganization of the brain in chronic pain is emphasized. We conclude by proposing a brain model for the transition of the human from acute to chronic pain.

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Pain and the brain: Specificity and plasticity of the brain in clinical chronic pain

Recently, local morphologic alterations of the brain in areas ascribable to the transmission of pain were detected in patients suffering from phantom pain, chronic back pain, irritable bowl syndrome, fibromyalgia and two types of frequent headaches. These alterations were different for each pain syndrome, but overlapped in the cingulate cortex, the orbitofrontal cortex, the insula and dorsal pons. These regions function as multi-integrative structures during the experience and the anticipation of pain. As it seems that chronic pain patients have a common "brain signature" in areas known to be involved in pain regulation, the question arises whether these changes are the cause or the consequence of chronic pain. The author suggests that the gray matter change observed in chronic pain patients are the consequence of frequent nociceptive input and should thus be reversible when pain is adequately treated.

Chronic pain may change the structure of the brain

Although chronic back pain is one of the most frequent reasons for permanent impairment in people under 65, the neurobiological mechanisms of chronification remain vague. Evidence suggests that cortical reorganisation, so-called functional plasticity, may play a role in chronic back pain patients. In the search for the structural counterpart of such functional changes in the CNS, we examined 18 patients suffering from chronic back pain with voxel-based morphometry and compared them to 18 sex and age matched healthy controls. We found a significant decrease of gray matter in the brainstem and the somatosensory cortex. Correlation analysis of pain unpleasantness and the intensity of pain on the day of scanning revealed a strong negative correlation (i.e. a decrease in gray matter with increasing unpleasantness/increasing intensity of pain) in these areas. Additionally, we found a significant increase in gray matter bilaterally in the basal ganglia and the left thalamus. These data support the hypothesis that ongoing nociception is associated with cortical and subcortical reorganisation on a structural level, which may play an important role in the process of the chronification of pain.

Altmeppen J

Papers

Affective components and intensity of pain correlate with structural differences in gray matter in chronic back pain patients