Modeling pain circuits: how imaging may modify perception.

Pain is the unpleasant sensory experience following tissue damage or the threat of damage. The activation of cortical regions during noxious stimulation is believed a result of the negative affect and sensations generated by the stimulus. How a noxious event is translated into pain experience remains uncertain, and pain that occurs in the absence of a noxious event remains mysterious. Acute pain and chronic pain depend on a categorization of feeling that occurs collectively rather than individually. Capturing that process inside a brain scan is problematic. Resolving this problem requires an approach to imaging that transgress the boundaries of physical and social concepts.