title: The primary somatosensory cortex and the insula contribute differently to the processing of transient and sustained nociceptive and non-nociceptive somatosensory inputs.
abstract: Transient nociceptive stimuli elicit consistent brain responses in the primary and secondary somatosensory cortices (S1, S2), the insula and the anterior and mid-cingulate cortex (ACC/MCC). However, the functional significance of these responses, especially their relationship with sustained pain perception, remains largely unknown. Here, using functional magnetic resonance imaging, we characterize the differential involvement of these brain regions in the processing of sustained nociceptive and non-nociceptive somatosensory input. By comparing the spatial patterns of activity elicited by transient (0.5 ms) and long-lasting (15 and 30 s) stimuli selectively activating nociceptive or non-nociceptive afferents, we found that the contralateral S1 responded more strongly to the onset of non-nociceptive stimulation as compared to the onset of nociceptive stimulation and the sustained phases of nociceptive and non-nociceptive stimulation. Similarly, the anterior insula responded more strongly to the onset of nociceptive stimulation as compared to the onset of non-nociceptive stimulation and the sustained phases of nociceptive and non-nociceptive stimulation. This suggests that S1 is specifically sensitive to changes in incoming non-nociceptive input, whereas the anterior insula is specifically sensitive to changes in incoming nociceptive input. Second, we found that the MCC responded more strongly to the onsets as compared to the sustained phases of both nociceptive and non-nociceptive stimulation, suggesting that it could be involved in the detection of change regardless of sensory modality. Finally, the posterior insula and S2 responded maximally during the sustained phase of non-nociceptive stimulation but not nociceptive stimulation, suggesting that these regions are preferentially involved in processing non-nociceptive somatosensory input.
authors.affiliation: Key Laboratory of Cognition and Personality (Ministry of Education) and Faculty of Psychology, Southwest University, Chongqing, China.
authors.forename: Li
authors.initials: L
authors.lastname: Hu
authors.affiliation: Center for Brain and Cognitive Sciences and Department of Psychology, Peking University, Beijing, China.
authors.forename: Li
authors.initials: L
authors.lastname: Zhang
authors.affiliation: Key Laboratory of Cognition and Personality (Ministry of Education) and Faculty of Psychology, Southwest University, Chongqing, China.
authors.forename: Rui
authors.initials: R
authors.lastname: Chen
authors.affiliation: Center for Brain and Cognitive Sciences and Department of Psychology, Peking University, Beijing, China.
authors.forename: Hongbo
authors.initials: H
authors.lastname: Yu
authors.affiliation: Research Center for Brain Function and Psychological Science, Shenzhen University, Shenzhen, China.
authors.forename: Hong
authors.initials: H
authors.lastname: Li
authors.affiliation: Institute of Neurosciences (IoNS), Université catholique de Louvain, Brussels, Belgium.
authors.forename: André
authors.initials: A
authors.lastname: Mouraux
mesh_terms: D000328:Adult; D000344:Afferent Pathways / Q000502:physiology; D001931:Brain Mapping / Q000379:methods*; D002540:Cerebral Cortex / Q000502:physiology*; D005260:Female; D006179:Gyrus Cinguli / Q000502:physiology*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D059225:Nociception / Q000502:physiology*; D013003:Somatosensory Cortex / Q000502:physiology*; D055698:Touch Perception / Q000502:physiology*; D055815:Young Adult
keywords: anterior and mid-cingulate cortex (ACC and MCC); functional magnetic resonance imaging (fMRI); operculo-insular cortex (OIC); pain; primary somatosensory cortex (S1); sustained brain responses