Pain-autonomic interactions: a selective review

The nociceptive and the autonomic systems interact a( the level of the periphery, spinal cord, brainstem, and forebrain. Spinal and visceral afferents provide converging information to spinothalamic neurons in the dorsal horn and to neurons of the nucleus tractus solitarius and parabrachial nuclei. These structures project to areas involved in reflex, homeostatic, and behavioral control of autonomic outflow, endocrine function, and nociception. These include monoaminergic cell groups of the medulla and pons, periaqueductal gray, hypothalamus, amygdala, insular cortex, and anterior cingulate gyrus. These interactions should be taken into account to understand the complex pathophysiology of chronic pain disorders.