Anticipatory coping of pain expressed in the human anterior cingulate cortex: a positron emission tomography study

We used positron emission tomography (PET) to monitor the regional cerebral blood flow (rCBF) as an index of brain activity in regions proposed to par ticipate in affective-motivational and cognitive-evaluative dimensions of p ain during anticipation of a noxious stimulation. Specifically we were inte rested in the anterior cingulate cortex (ACC), the ventromedial prefrontal cortex (VMPFC) and the periaqueductal grey (PAG). Anticipating an unpredict able and unlearned pain stimulus activated the right ACC, the VMPFC and the FAG while anticipating a learned pain-stimulus resulted in a decreased act ivity in the ACC and the VMPFC. These patterns are compatible with two face ts of affect-laden cognitive coping: alertness and attention-distraction. T he right-preponderant expression of the changes in the ACC supports the hyp othesis of a preferential role of the non-dominant hemisphere in negative e motional processing. The data demonstrate an anticipatory coping mechanism and illustrate a neurophysiological process underlying the modulation of at tention to pain. (C) 1999 Published by Elsevier Science Ireland Ltd. All ri ghts reserved.