The challenge of pain

abnormal activity acupuncture afferent anaesthesia anaesthetic analgesia analgesic axons behaviour biofeedback block blood body brain brainstem cancer causalgia cells central nervous system chronic pain clinical cordotomy cortex damage decrease descending disease dorsal column dorsal horn dose drugs effects electrical stimulation evidence evoked exciting experience feel Figure gate gate-control theory hospital hypnosis inhibition inhibitory injection injury intensity lamina lesions low back pain major mechanisms Melzack morphine muscle narcotics nerve fibres nerve impulses neural neurons Noordenbos normal noxious occur operation pain relief pain syndromes pathways patients pattern peripheral nerve phantom limb pain physiological placebo pressure problems procedures produce pain prolonged psychological recent receptive fields receptors relief of pain response reticular formation role sensation sensory input severe pain signals skin small fibres specific spinal cord substantia gelatinosa suffering summation surgery surgical sympathetic techniques terminals thalamus therapy tion tissue tract transmission treatment trigger points Wall