Comparing neural responses to cutaneous heat and pressure pain in healthy participants.

Even though acute pain comes in many different shapes and forms, a lot of experimental pain studies predominantly employ cutaneous heat pain. This makes a comparison between different pain types and the link between findings from these experimental studies to clinical pain difficult. To bridge this gap, we investigated both cuff pressure pain and cutaneous heat pain using a within-subject design in combination with functional magnetic resonance imaging (fMRI). Noxious stimuli were applied with a 17-s duration at three different intensities above the pain threshold using a thermode and a computer-controlled cuff pressure device. Both pain modalities led to contralateral activation in the anterior insula and parietal operculum. Heat pain showed greater activation in the precentral gyrus, pontine reticular nucleus, and dorsal posterior insula, whilst pressure pain showed greater activation in the primary somatosensory cortex and bilateral superior parietal lobules. Most importantly, the time course of the fMRI signal changes differed between modalities, with pressure pain peaking in the first stimulus half, whereas heat pain led to a prolonged and increasing response across the stimulus duration with a peak in the second stimulus half. Our findings suggest that pressure and heat pain lead to common as well as different (temporal) activation patterns in key pain processing regions.