fMRI signal increases in the contralateral insula and in aMCC, but not in the parietal cortex, were more prolonged following painful than tactile stimuli. Significant decreases in fMRI signals following both tactile and painful stimuli were found in perigenual cingulate (pACC)/medial prefrontal cortex (MPF) and in the posterior cingulate/precuneus/paracentral lobule more intense decreases were found in the pACC/MPF following painful stimuli. Higher activity following noxious stimulation was found in the contralateral mid-anterior insular cortex, in the anterior mid-cingulate cortex (aMCC) and in the adjacent dorso-medial frontal cortex. The fMRI signal increases following brief mechanical noxious or non-noxious stimulation of the hand dorsum were largely overlapping in the contralateral and ipsilateral hemispheres, including portions of the parietal, insular, frontal and cingulate cortices. To this end, we adopted an event-related functional magnetic resonance imaging (fMRI) paradigm allowing us to separately assess the activity related to stimulus anticipation, perception, and coding. In the present study, we investigated similarities and differences between the spatial and temporal patterns of brain activity related to touch vs.
Most imaging studies on the human pain system have concentrated so far on the spatial distribution of pain-related activity.
