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

Key Points Pain experience can be profoundly influenced by emotional states and attentional direction. Multiple brain regions involved in pain processing are also crucial for emotion and attention. Emotional modulation of pain seems to be controlled by a fronto–periaqueductal grey–brainstem circuit that can increase or decrease pain experience depending on the emotion being experienced: for example, empathy for another's pain can increase an individual's own pain sensation. Attention can reduce pain via distraction and is purported to depend on insula–parietal–somatosensory corticocortical pathways. Both emotional and attentional modulation of pain can be harnessed by non-pharmacological interventions such as yoga, meditation and the placebo effect. Indeed, even expectation of relief activates descending endogenous opioidergic circuitry. When pain becomes chronic, structural changes are seen in multiple brain regions involved in emotional and attentional aspects of pain modulation, possibly leading to a diminished ability in pain regulation. There is also evidence that disruption of endogenous pain modulatory systems by chronic pain alters cognitive and emotional processing in patients with pain, leading to impairments in performance on decision-making and learning tasks. The neurochemical bases for these changes are not yet well understood, although evidence suggests possible roles for excitotoxicity and neuroinflammation in impaired neuronal integrity and firing properties. However, successful treatment of chronic pain — such as by hip replacement or back surgery — can reverse the pain-related reductions in grey matter. There are tantalizing hints that psychology-based treatments such as meditation may also act in a neuroprotective manner to prevent or reverse these pain-related changes in brain structure and function. Chronic pain is associated with changes in brain structure and function resulting in altered cognition and affect. Bushnell et al . examine the mechanisms underlying the psychological modulation of pain and the potential of mind–body therapies to alleviate chronic pain. 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