TY - JOUR
T1 - Area-specific representation of mechanical nociceptive stimuli within SI cortex of squirrel monkeys
AU - Chen, Li Min
AU - Friedman, Robert M.
AU - Roe, Anna Wang
N1 - Funding Information:
We thank F.L. Healy for excellent technical assistance. This work was supported by Grants from NIH NS044375 (A.W.R.), NIH DE016606 (L.M.C.) and the Packard (A.W.R.) and Brown-Coxe Foundations (L.M.C.).
PY - 2009/2
Y1 - 2009/2
N2 - While functional imaging studies in humans have consistently reported activation of primary somatosensory cortex (SI) with painful stimuli, the specific roles of subdivisions of areas 3a, 3b, and 1 within SI during pain perception are largely unknown, particularly in the representation of mechanical evoked pain. In this study, we investigated how modality, location, and intensity of nociceptive stimuli are represented within SI by using high-spatial resolution optical imaging of intrinsic signals in Pentothal-anesthetized squirrel monkeys. Perceptually comparable mechanical nociceptive and innocuous tactile stimuli were delivered by indenting the glabrous skin of the distal finger pads with 0.2 and 2 mm diameter probes, respectively. Within each of areas 3a, 3b, and 1, activations to mechanical nociceptive stimulation of individual distal finger pads were spatially distinct and somatotopically organized. We observed differential cortical activation patterns. Areas 3a, 3b, and 1 were all activated during mechanical nociceptive stimulation and were modulated by nociceptive stimulus intensity. However, with innocuous tactile stimulation, mainly areas 3b and 1 exhibited response modulation with different levels of stimulation. In summary, mechanical nociceptive inputs are area-specific and topographically represented within SI. We propose that all areas of SI are implicated in encoding the features of mechanical nociception, where areas 3a and 3b are distinctively involved in coding nociceptive and pressure sensation components of stimulation.
AB - While functional imaging studies in humans have consistently reported activation of primary somatosensory cortex (SI) with painful stimuli, the specific roles of subdivisions of areas 3a, 3b, and 1 within SI during pain perception are largely unknown, particularly in the representation of mechanical evoked pain. In this study, we investigated how modality, location, and intensity of nociceptive stimuli are represented within SI by using high-spatial resolution optical imaging of intrinsic signals in Pentothal-anesthetized squirrel monkeys. Perceptually comparable mechanical nociceptive and innocuous tactile stimuli were delivered by indenting the glabrous skin of the distal finger pads with 0.2 and 2 mm diameter probes, respectively. Within each of areas 3a, 3b, and 1, activations to mechanical nociceptive stimulation of individual distal finger pads were spatially distinct and somatotopically organized. We observed differential cortical activation patterns. Areas 3a, 3b, and 1 were all activated during mechanical nociceptive stimulation and were modulated by nociceptive stimulus intensity. However, with innocuous tactile stimulation, mainly areas 3b and 1 exhibited response modulation with different levels of stimulation. In summary, mechanical nociceptive inputs are area-specific and topographically represented within SI. We propose that all areas of SI are implicated in encoding the features of mechanical nociception, where areas 3a and 3b are distinctively involved in coding nociceptive and pressure sensation components of stimulation.
KW - Digit
KW - Intrinsic optical imaging
KW - Mechanical nociception
KW - Primary somatosensory cortex
KW - Primate
KW - Touch
UR - http://www.scopus.com/inward/record.url?scp=58749106226&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=58749106226&partnerID=8YFLogxK
U2 - 10.1016/j.pain.2008.11.018
DO - 10.1016/j.pain.2008.11.018
M3 - Article
C2 - 19136211
AN - SCOPUS:58749106226
SN - 0304-3959
VL - 141
SP - 258
EP - 268
JO - Pain
JF - Pain
IS - 3
ER -