Real time fMRI feedback of the anterior cingulate and posterior insular cortex in the processing of pain.

Self-regulation of brain activation using real-time functional magnetic resonance imaging has been used to train subjects to modulate activation in various brain areas and has been associated with behavioral changes such as altered pain perception. The aim of this study was to assess the comparability of upregulation versus downregulation of activation in the rostral anterior cingulate cortex (rACC) and left posterior insula (pInsL) and its effect on pain intensity and unpleasantness. In a first study, we trained 10 healthy subjects to separately upregulate and downregulate the blood oxygenation level-dependent response in the rACC or pInsL (six trials on 4 days) in response to painful electrical stimulation. The participants learned to significantly downregulate activation in pInsL and rACC and upregulate pInsL but not rACC. Success in the modulation of one region and direction of the modulation was not significantly correlated with success in another condition, indicating that the ability to control pain-related brain activation is site-specific. Less covariation between the areas in response to the nociceptive stimulus was positively correlated with learning success. Upregulation or downregulation of either region was unrelated to pain intensity or unpleasantness; however, our subjects did not learn rACC upregulation, which might be important for pain control. A significant increase in pain unpleasantness was found during upregulation of pInsL when covariation with the rACC was low. These initial results suggest that the state of the network involved in the processing of pain needs to be considered in the modulation of pain-evoked activation and its behavioral effects.