Scalp topography and dipolar source modelling of potentials evoked by CO2 laser stimulation of the hand

Valeriani, Massimiliano; Rambaud, Loı̈c; Mauguı̀ere, François

doi:10.1016/0168-5597(96)95625-7

Cited by 231 publications

(141 citation statements)

References 73 publications

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“…The location of the pMCC responses is consistent with that of CC sources identified by dipolar modeling of scalp LEPs (Tarkka and Treede, 1993;Valeriani et al, 1996) (for review, see Garcia-Larrea et al, 2003). However, modeled MCC dipoles are most often reported to peak at 220 -340 ms (N2-P2 LEPs), i.e., at latencies consistent with the late intracortical response that we identified in six of our nine patients.…”

Section: Response Localizationsupporting

confidence: 62%

“…However, modeled MCC dipoles are most often reported to peak at 220 -340 ms (N2-P2 LEPs), i.e., at latencies consistent with the late intracortical response that we identified in six of our nine patients. The reasons why the early pMCC activities may not be easily individualized by source modeling of scalp recordings are multiple: (1) a low-pass filter effect of skull, corticospinal fluid, and meninges that tends to lump together multiple sources with similar location (Nunez and Srinivasan, 2005); (2) an orientation of the early pMCC LEP dipolar source that may render this component difficult to record by surface (or even subdural) electrodes; (3) the contribution of other sources in the building of the scalp LEPs including the posterior parietal, amygdalohippocampal, and/or anterior insular regions (Valeriani et al, 1996;Cruccu et al, 2003). Notwithstanding such difficulties, Schlereth et al (2003) were able to model early LEP cingulate sources in the pMCC peaking only 50 ms later than the intracortical activities reported here.…”

Section: Response Localizationmentioning

confidence: 99%

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Parallel Processing of Nociceptive A-δ Inputs in SII and Midcingulate Cortex in Humans

Frot¹,

Mauguı̀ere²,

Magnin³

et al. 2008

J. Neurosci.

137

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The cingulate cortex (CC) as a part of the "medial" pain subsystem is generally assumed to be involved in the affective and/or cognitive dimensions of pain processing, which are viewed as relatively slow processes compared with the sensory-discriminative pain coding by the lateral second somatosensory area (SII)-insular cortex. The present study aimed at characterizing the location and timing of the CC evoked responses during the 1 s period after a painful laser stimulus, by exploring the whole rostrocaudal extent of this cortical area using intracortical recordings in humans. Only a restricted area in the median CC region responded to painful stimulation, namely the posterior midcingulate cortex (pMCC), the location of which is consistent with the so-called "motor CC" in monkeys. Cingulate pain responses showed two components, of which the earliest peaked at latencies similar to those obtained in SII. These data provide direct evidence that activations underlying the processing of nociceptive information can occur simultaneously in the "medial" and "lateral" subsystems. The existence of short-latency pMCC responses to pain further indicates that the "medial pain system" is not devoted exclusively to the processing of emotional information, but is also involved in fast attentional orienting and motor withdrawal responses to pain inputs. These functions are, not surprisingly, conducted in parallel with pain intensity coding and stimulus localization specifically subserved by the sensory-discriminative "lateral" pain system.

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Section: Response Localizationsupporting

confidence: 62%

Section: Response Localizationmentioning

confidence: 99%

Parallel Processing of Nociceptive A-δ Inputs in SII and Midcingulate Cortex in Humans

Frot¹,

Mauguı̀ere²,

Magnin³

et al. 2008

J. Neurosci.

137

View full text Add to dashboard Cite

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“…They were labelled according to Valeriani et al [18]. LEP amplitudes and latencies were measured from the baseline on the CZ and T3 derivations.…”

Section: Laser-evoked Potentialsmentioning

confidence: 99%

“…The location of the impact on the skin was slightly shifted between two successive stimuli, to avoid the sensitisation of the nociceptors. CO2 laser stimuli were delivered at a fixed power of 7.5 W and duration of 25 ms [18], which was perceived by all patients and controls as a painful pinprick. We were careful to settle the laser power and duration at a suprathreshold level in all cases [18], using a 10-point visual analogue scale (VAS) in which '0' corresponds to no sensation, '4' to the Pain Threshold and '10' to intolerable pain.…”

Section: Laser-evoked Potentialsmentioning

confidence: 99%

“…CO2 laser stimuli were delivered at a fixed power of 7.5 W and duration of 25 ms [18], which was perceived by all patients and controls as a painful pinprick. We were careful to settle the laser power and duration at a suprathreshold level in all cases [18], using a 10-point visual analogue scale (VAS) in which '0' corresponds to no sensation, '4' to the Pain Threshold and '10' to intolerable pain. In all patients and controls the 25-ms duration and 7.5-W intensity laser stimuli were judged as a painful pinprick, with a VAS value ≥6 in more than 50% of 20 stimuli on both the examined sites.…”

Section: Laser-evoked Potentialsmentioning

confidence: 99%

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Effects of remote cutaneous pain on trigeminal laser-evoked potentials in migraine patients

et al. 2007

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The present study aimed to evaluate heat pain thresholds and evoked potentials following CO2 laser thermal stimulation (laser-evoked potentials, LEPs), during remote application of capsaicin, in migraine patients vs. non-migraine healthy controls. Twelve outpatients suffering from migraine without aura were compared with 10 healthy controls. The LEPs were recorded by 6 scalp electrodes, stimulating the dorsum of the right hand and the right supraorbital zone in basal condition, during the application of 3% capsaicin on the dorsum of the left hand and after capsaicin removal. In normal subjects, the laser pain and the N2-P2 vertex complex obtained by the hand and face stimulation were significantly reduced during remote capsaicin application, with respect to preand post-capsaicin conditions, while in migraine LEPs and laser pain were not significantly modified during remote painful stimulation. In migraine a defective brainstem inhibiting control may coexist with cognitive factors of focalised attention to facial pain, less sensitive to distraction by a second pain.

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Assessment of trigeminal small-fiber function: brain and reflex responses evoked by CO2-laser stimulation

Cruccu¹,

Romaniello²,

Amantini³

et al. 1999

Muscle Nerve

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Laser pulses selectively excite mechano‐thermal nociceptors and evoke brain potentials that may reveal small‐fiber dysfunction. We applied CO2‐laser pulses to the perioral and supraorbital regions and recorded the scalp laser‐evoked potentials (LEPs) and reflex responses in the orbicularis oculi, masticatory, and neck muscles in 30 controls and 10 patients with facial sensory disturbances. Low‐intensity pulses readily evoked scalp potentials consisting of a negative component with a latency of 165 ms followed by a positive component at 250 ms. In vertex recordings, the amplitude of LEPs exceeded 30 μV. Although only high‐intensity pulses evoked reflex responses, some subjects showed—even to low‐intensity pulses—an orbicularis oculi (blink‐like) response that markedly contaminated the scalp recording. Scalp LEPs were abnormal in patients with hypalgesia and normal trigeminal reflexes and normal in patients with normal pain sensitivity and abnormal trigeminal reflexes. Possibly because of the high receptor density in this area and the short conduction distance, laser stimulation of the trigeminal territory yields low‐threshold and large LEPs, which are useful for detecting dysfunction in peripheral and central pain pathways. © 1999 John Wiley & Sons, Inc. Muscle Nerve 22: 508–516, 1999.

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Scalp topography and dipolar source modelling of potentials evoked by CO2 laser stimulation of the hand

Cited by 231 publications

References 73 publications

Parallel Processing of Nociceptive A-δ Inputs in SII and Midcingulate Cortex in Humans

Parallel Processing of Nociceptive A-δ Inputs in SII and Midcingulate Cortex in Humans

Effects of remote cutaneous pain on trigeminal laser-evoked potentials in migraine patients

Assessment of trigeminal small-fiber function: brain and reflex responses evoked by CO2-laser stimulation

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