Title
Nociceptive and non-nociceptive sub-regions in the human secondary somatosensory cortex: an MEG study using fMRI constraints.
Abstract
Previous evidence from functional magnetic resonance imaging (fMRI) has shown that a painful galvanic stimulation mainly activates a posterior sub-region in the secondary somatosensory cortex (SII), whereas a non-painful sensory stimulation mainly activates an anterior sub-region of SII [Ferretti, A., Babiloni, C., Del Gratta, C., Caulo, M., Tartaro, A., Bonomo, L., Rossini, P.M., Romani, G.L., 2003. Functional topography of the secondary somatosensory cortex for non-painful and painful stimuli: an fMRI study. Neuroimage 20 (3), 1625–1638.]. The present study, combining fMRI with magnetoencephalographic (MEG) findings, assessed the working hypothesis that the activity of such a posterior SII sub-region is characterized by an amplitude and temporal evolution in line with the bilateral functional organization of nociceptive systems. Somatosensory evoked magnetic fields (SEFs) recordings after alvanic median nerve stimulation were obtained from the same sample of subjects previously examined with fMRI [Ferretti, A., Babiloni, C., Del Gratta, C., Caulo, M., Tartaro, A., Bonomo, L., Rossini, P.M., Romani, G.L., 2003. Functional topography of the secondary somatosensory cortex for non-painful and painful stimuli: an fMRI study. Neuroimage 20 (3), 1625–1638.]. Constraints for dipole source localizations obtained from MEG recordings were applied according to fMRI activations, namely, at the posterior and the anterior SII sub-regions. It was shown that, after painful stimulation, the two posterior SII sub-regions of the contralateral and ipsilateral hemispheres were characterized by dipole sources with similar amplitudes and latencies. In contrast, the activity of anterior SII sub-regions showed statistically significant differences in amplitude and latency during both non-painful and painful stimulation conditions. In the contralateral hemisphere, the source activity was greater in amplitude and shorter in latency with respect to the ipsilateral. Finally, painful stimuli evoked a response from the posterior sub-regions peaking significantly earlier than from the anterior sub-regions. These results suggested that both ipsi and contra posterior SII sub-regions process painful stimuli in parallel, while the anterior SII sub-regions might play an integrative role in the processing of somatosensory stimuli.
Year
DOI
Venue
2005
10.1016/j.neuroimage.2005.01.012
NeuroImage
Keywords
Field
DocType
Magnetoencephalography,SEF,Secondary somatosensory area (SII),Median-nerve electrical stimulation,Pain
Developmental psychology,Secondary somatosensory cortex,Neuroscience,Functional magnetic resonance imaging,Somatosensory evoked potential,Psychology,Somatosensory system,Stimulus (physiology),Stimulation,Sensory stimulation therapy,Magnetoencephalography
Journal
Volume
Issue
ISSN
26
1
1053-8119
Citations 
PageRank 
References 
4
0.58
4
Authors
9
Name
Order
Citations
PageRank
K Torquati1264.66
V Pizzella220024.54
Claudio Babiloni310016.77
C Del Gratta4644.51
S Della Penna5628.00
A Ferretti640.58
R Franciotti7506.99
P M Rossini8489.67
G L Romani911312.58