--Central Pain syndrome, or post-stroke syndrome, which can occur when sensory nerve tracts in the spinothalamic region of the brain are damaged.

Stroke is not the only cause of this, but it seems to be the most common (people who have multiple sclerosis legions in the thalamus, or have had degeneration there as a result of B12 deficiency of a number of other brain conditions have reported it as well).

See

www.centralpain.com

www.centralpain.org