Cognitive modulation of pain: how do attention and emotion influence pain processing?

There have been anecdotal accounts for centuries of people apparently experiencing little or no pain in situations that most of us would find excruciating. Yet, western medicine has given little credence to a patient’s ability to modify pain. Instead, we focus on the pharmacological control of pain. For this reason, the vast majority of research on pain control has concentrated on peripheral and spinal cord mechanisms of opioid and anti-inflammatory analgesic therapy. Nevertheless, researchers are beginning to recognize that a variety of pain modulatory mechanisms exist in the nervous system, and these modulatory systems can be accessed either pharmacologically or through contextual and/or cognitive manipulation (Fields, 2000). Variables such as attentional state, emotional context, hypnotic suggestions, attitudes, expectations or anesthesia-induced changes in consciousness now have been shown to alter both pain perception and forebrain pain transmission in humans. These techniques, at times, preferentially alter sensory and/or affective aspects of pain perception, and the associated modulation of pain-evoked neural activity occurs in limbic and/or sensory brain regions, suggesting multiple endogenous pain-modulatory systems. This paper compares the modulatory influences of two principal cognitive variables, attention and emotion, on pain perception and addresses possible neural mechanisms underlying each of these influences.