Background The somatosensory cortex has been inconsistently activated in pain studies and the functional properties of subregions within this cortical area are poorly understood. To address this we used magnetoencephalography (MEG), a brain imaging technique capable of recording changes in cortical neural activity in real-time, to investigate the functional properties of the somatosensory cortex during different phases of the visceral pain experience. Methods In eight participants (4 male), 151-channel whole cortex MEG was used to detect cortical neural activity during 25 trials lasting 20 seconds each. Each trial comprised four separate periods of 5 seconds in duration. During each of the periods, different visual cues were presented, indicating that period 1=rest, period 2=anticipation, period 3=pain and period 4=post pain. During period 3, participants received painful oesophageal balloon distensions (four at 1 Hz). Regions of cortical activity were identified using Synthetic Aperture Magnetometry (SAM) and by the placement of virtual electrodes in regions of interest within the somatosensory cortex, time-frequency wavelet plots were generated. Results SAM analysis revealed significant activation with the primary (S1) and secondary (S2) somatosensory cortices. The time-frequency wavelet spectrograms showed that activation in S1 increased during the anticipation phase and continued during the presentation of the stimulus. In S2, activation was tightly time and phase-locked to the stimulus within the pain period. Activations in both regions predominantly occurred within the 10–15 Hz and 20–30 Hz frequency bandwidths. Discussion These data are consistent with the role of S1 and S2 in the sensory discriminatory aspects of pain processing. Activation of S1 during anticipation and then pain may be linked to its proposed role in attentional as well as sensory processing. The stimulus-related phasic activity seen in S2 demonstrates that this region predominantly encodes information pertaining to the nature and intensity of the stimulus.
|Publication status||Published - Apr 2006|
|Event||Annual Meeting of the British-Society-of-Gastroenterology, Surgical Section in Association with the Association of Coloproctology (ACPGBI) and IBD Section joint symposium - Birmingham , United Kingdom|
Duration: 20 Mar 2006 → 23 Mar 2006
|Other||Annual Meeting of the British-Society-of-Gastroenterology, Surgical Section in Association with the Association of Coloproctology (ACPGBI) and IBD Section joint symposium|
|Period||20/03/06 → 23/03/06|
Bibliographical noteAbstract published in Gut, 55 (Suppl. 2): A112-113. 0017-5749.
- somatosensory cortex
- pain studies
- cortical area
- cortical neural activity
- visceral pain experience