Figure 3.

Segregating brain activity for acute thermal pain perception between anticipation, perception and pain relief identifies distinct networks sequentially activated during perception of acute pain. Three vectors separated in time were contrasted for a thermal painful stimulus that was a randomized sequence of stimuli where intensity duration and inter-stimulus intervals were not predictable. The anticipation vector identified increased activity preferentially related to only the start of the stimulus; while perception was identified by subjective ratings of pain; and relief period was identified for increased activity in the time window when the stimulus was returning to baseline. A. Three separate and complimentary networks are identified. B. Differential activity for the three phases of pain perception is illustrated for indicated regions (green circles in A) (A = anticipation, P = perception, R = relief). Data are derived from the study described in [12].