Cortical representation of pain in primary sensory-motor areas (S1/M1)—a study using intracortical recordings in humans
Article first published online: 15 JUN 2012
Copyright © 2012 Wiley Periodicals, Inc.
Human Brain Mapping
Volume 34, Issue 10, pages 2655–2668, October 2013
How to Cite
Frot, M., Magnin, M., Mauguière, F. and Garcia-Larrea, L. (2013), Cortical representation of pain in primary sensory-motor areas (S1/M1)—a study using intracortical recordings in humans. Hum. Brain Mapp., 34: 2655–2668. doi: 10.1002/hbm.22097
- Issue published online: 12 SEP 2013
- Article first published online: 15 JUN 2012
- Manuscript Accepted: 14 MAR 2012
- Manuscript Revised: 12 MAR 2012
- Manuscript Received: 7 NOV 2011
- somatosensory cortex;
- motor cortex;
- evoked potentials;
Intracortical evoked potentials to nonnoxious Aβ (electrical) and noxious Aδ (laser) stimuli within the human primary somatosensory (S1) and motor (M1) areas were recorded from 71 electrode sites in 9 epileptic patients. All cortical sites responding to specific noxious inputs also responded to nonnoxious stimuli, while the reverse was not always true. Evoked responses in S1 area 3b were systematic for nonnoxious inputs, but seen in only half of cases after nociceptive stimulation. Nociceptive responses were systematically recorded when electrode tracks reached the crown of the postcentral gyrus, consistent with an origin in somatosensory areas 1–2. Sites in the precentral cortex also exhibited noxious and nonnoxious responses with phase reversals indicating a local origin in area 4 (M1). We conclude that a representation of thermal nociceptive information does exist in human S1, although to a much lesser extent than the nonnociceptive one. Notably, area 3b, which responds massively to nonnoxious Aβ activation was less involved in the processing of noxious heat. S1 and M1 responses to noxious heat occurred at latencies comparable to those observed in the supra-sylvian opercular region of the same patients, suggesting a parallel, rather than hierarchical, processing of noxious inputs in S1, M1 and opercular cortex. This study provides the first direct evidence for a spinothalamic related input to the motor cortex in humans. Hum Brain Mapp 34:2655–2668, 2013. © 2012 Wiley Periodicals, Inc.