Previous neuroimaging studies have shown brain activity during not only the application of
noxious stimuli, but also prior to stimulation. The functional significance of the anticipatory
response, however, has yet to be explored. Two theoretical responses involve either a
decrease or an increase in sensitivity of the nociceptive system. In a functional magnetic
resonance imaging (fMRI) study, brainstem responses during anticipation and processing of
thermal noxious stimuli were investigated. Twelve healthy subjects were warned prior to and …