TY - JOUR
T1 - Serial processing in primary and secondary somatosensory cortex
T2 - A DCM analysis of human fMRI data in response to innocuous and noxious electrical stimulation
AU - Khoshnejad, Mina
AU - Piché, Mathieu
AU - Saleh, Soha
AU - Duncan, Gary
AU - Rainville, Pierre
N1 - Funding Information: This research was funded by the Canadian Institutes of Health Research (CIHR, MOP82722 and MOP86541 ). Burses and salary support was obtained from the “ Fonds de recherche Québec–Santé (FRSQ) ” (M.P. and P.R.), the CIHR (M.P.), and the “ Fondation de recherche chiropratique du Québec (M.P.). This study was performed with the technical help of Leo Tenbokum and of Carollyn Hurst and André Cyr from the “Unité de Neuroimagerie Fonctionnelle” of the “Centre de recherche de l’Institut universitaire de gériatrie de Montréal”.
PY - 2014/8/8
Y1 - 2014/8/8
N2 - The anatomy of the somatosensory system allows both serial and parallel information flow but the conditions involving each mode of processing is a matter of debate. In this functional magnetic resonance imaging (fMRI) study, cutaneous electrical stimulation was applied to human volunteers at three intensities (low-innocuous, moderate-noxious and high-noxious) to investigate interactions between contralateral primary and secondary somatosensory cortices (S1c and S2c), and between contralateral and ipsilateral S2 (S2c and S2i), using dynamic causal modeling (DCM). Our results are consistent with serial processing with a key role of the direct input to S1c for all three intensity levels. The more intense stimulus also induced significantly more interactions between S2i and S2c, consistent with an increase in inter-hemispheric integration associated with the additional recruitment of nociceptive inputs. However, stronger pain reports were also associated with reduced information flow from S1c to S2c at both the moderate (r= -0.81, p= 0.004) and the high stimulation level (r= -0.63, p= 0.037). These findings suggest that the connectivity pattern driven by innocuous inputs is modified by the additional activation of nociceptive afferents.
AB - The anatomy of the somatosensory system allows both serial and parallel information flow but the conditions involving each mode of processing is a matter of debate. In this functional magnetic resonance imaging (fMRI) study, cutaneous electrical stimulation was applied to human volunteers at three intensities (low-innocuous, moderate-noxious and high-noxious) to investigate interactions between contralateral primary and secondary somatosensory cortices (S1c and S2c), and between contralateral and ipsilateral S2 (S2c and S2i), using dynamic causal modeling (DCM). Our results are consistent with serial processing with a key role of the direct input to S1c for all three intensity levels. The more intense stimulus also induced significantly more interactions between S2i and S2c, consistent with an increase in inter-hemispheric integration associated with the additional recruitment of nociceptive inputs. However, stronger pain reports were also associated with reduced information flow from S1c to S2c at both the moderate (r= -0.81, p= 0.004) and the high stimulation level (r= -0.63, p= 0.037). These findings suggest that the connectivity pattern driven by innocuous inputs is modified by the additional activation of nociceptive afferents.
KW - DCM
KW - Electrical stimulations
KW - Intensity encoding
KW - Serial processing
KW - Somatosensory cortex
UR - http://www.scopus.com/inward/record.url?scp=84903456868&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84903456868&partnerID=8YFLogxK
U2 - 10.1016/j.neulet.2014.06.013
DO - 10.1016/j.neulet.2014.06.013
M3 - Article
C2 - 24933536
SN - 0304-3940
VL - 577
SP - 83
EP - 88
JO - Neuroscience Letters
JF - Neuroscience Letters
ER -