Region-specific encoding of sensory and affective components of pain in the human brain: A positron emission tomography correlation analysis

Brain imaging with positron emission tomography has identified some of the principal cerebral structures of a central network activated by pain. To di scover whether the different cortical and subcortical areas process differe nt components of the multidimensional nature of pain, we performed a regres sion analysis between noxious heat-related regional blood flow increases an d experimental pain parameters reflecting detection of pain, encoding of pa in intensity, as well as pain unpleasantness. The results of our activation study indicate that different functions in pain processing can be attribut ed to different brain regions; ie, the gating function reflected by the pai n threshold appeared to be related to anterior cingulate cortex, the fronta l inferior cortex, and the thalamus, the coding of pain intensity to the pe riventricular gray as well as to the posterior cingulate cortex, and the en coding of pain unpleasantness to the posterior sector of the anterior cingu late cortex.