Thalamus and pain.

The thalamus is a key relay station for the transmission of nociceptive information to the cerebral cortex. We review the input-output connection, functional imaging, direct neuronal recording, stimulation, and lesioning studies on the involvement of thalamus in acute and chronic pain functions. Based on its specific reciprocal connection with the cerebral cortex, strong nociceptive responsiveness, and the severe chronic pain when it is damaged, the thalamus may hold the key to pain consciousness and the key to understanding spontaneous and evoked pain in chronic pain conditions. A work plan is proposed for future study.