MATCH AND MISMATCH - IDENTIFYING THE NEURONAL DETERMINANTS OF PAIN

Despite the increased intensity and sophistication of research on pain mechanisms in the past three decades, serious uncertainties remain ab out the neuronal origin of pain, especially in painful clinical condit ions. Although a positive correlation between nociceptive afferent act ivity and the subjective perception of pain has been seen under contro lled experimental conditions, important mismatches point to the critic al importance of central nervous system processes as determinants of p ain. Multiple peripheral, segmental, and supraspinal neuronal activiti es control nociceptive processing at all levels of the neuraxis. Three studies in this issue highlight the problem of identifying the neuron al determinants of pain by addressing contrasting mismatches: angina-l ike chest pain without an obvious cause and a potential source of angi na (myocardial ischemia) without pain. The results of these studies su ggest that selective visceral hyperalgesia and hypoalgesia of peripher al or central origin may be present without other clinical evidence fo r neurologic abnormality. Complex mechanisms interacting at several le vels of the nervous system appear to be involved.