C- and Aδ-fiber components of heat-evoked cerebral potentials in healthy human subjects

Walter Magerl, Zahid Ali, Jens Ellrich, Richard Meyer, Rolf Detlef Treede

Research output: Contribution to journalReview article

Abstract

Feedback-controlled laser heat was used to stimulate the hairy skin of the hand dorsum and forearm, and heat-evoked cerebral potentials were recorded at midline (Fz, Cz, Pz) and temporal (T3, T4) scalp positions. Based on data from primary afferent electrophysiology a stimulus level (40°C) was chosen, which is above C-fiber heat threshold, but clearly below Aδ-nociceptor heat threshold in order to excite selectively C-fibers without concomitant excitation of Aδ-fibers. Feedback-controlled stepped heat stimuli to 40°C elicited ultralate laser evoked potentials (LEPs) at the vertex in a high proportion of experiments (90%). Estimates of conduction velocity calculated from latency shifts between the hand and forearm sites of ultralate LEPs (2.4 m/s) and of reaction times (2.8 m/s) confirmed mediation of ultralate potentials by unmyelinated nerve fibers (nociceptors and/or warm fibers). The ultralate LEP could be differentiated from resolution of contingent negative variation (CNV), an endogenous potential related to expectation and response preparation, by its scalp topography. Strong heat stimuli of 48°C, which is suprathreshold for most Aδ- and C-fiber nociceptors, elicited the well-known late LEPs mediated by nociceptive Aδ-fibers confirming previous studies. The LEP waveform to strong heat stimuli also contained an ultralate component reminiscent of an ultralate LEP following the late LEP. Ultralate and late LEP had identical scalp topography. In conclusion, the method of temperature-controlled laser heat stimuli allows the selective and reliable examination of Aδ- and C-fiber-mediated afferent pathways and the related cortical processing without the complication of dissociating A-fiber nerve blocks. Copyright (C) 1999 International Association for the Study of Pain. Published by Elsevier Science B.V.

Original languageEnglish (US)
Pages (from-to)127-137
Number of pages11
JournalPain
Volume82
Issue number2
DOIs
StatePublished - Aug 1 1999

Fingerprint

Myelinated Nerve Fibers
Evoked Potentials
Healthy Volunteers
Unmyelinated Nerve Fibers
Hot Temperature
Nociceptors
Scalp
Forearm
Lasers
Hand
Contingent Negative Variation
Afferent Pathways
Laser-Evoked Potentials
Nerve Block
Electrophysiology
Reaction Time
Skin
Temperature

Keywords

  • Aδ-fibers
  • C-fibers
  • Evoked potentials
  • First pain
  • Infrared laser
  • Late potentials
  • Second pain
  • Ultralate potentials

ASJC Scopus subject areas

  • Clinical Neurology
  • Psychiatry and Mental health
  • Neurology
  • Neuroscience(all)
  • Pharmacology
  • Clinical Psychology

Cite this

C- and Aδ-fiber components of heat-evoked cerebral potentials in healthy human subjects. / Magerl, Walter; Ali, Zahid; Ellrich, Jens; Meyer, Richard; Treede, Rolf Detlef.

In: Pain, Vol. 82, No. 2, 01.08.1999, p. 127-137.

Research output: Contribution to journalReview article

Magerl, Walter ; Ali, Zahid ; Ellrich, Jens ; Meyer, Richard ; Treede, Rolf Detlef. / C- and Aδ-fiber components of heat-evoked cerebral potentials in healthy human subjects. In: Pain. 1999 ; Vol. 82, No. 2. pp. 127-137.
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abstract = "Feedback-controlled laser heat was used to stimulate the hairy skin of the hand dorsum and forearm, and heat-evoked cerebral potentials were recorded at midline (Fz, Cz, Pz) and temporal (T3, T4) scalp positions. Based on data from primary afferent electrophysiology a stimulus level (40°C) was chosen, which is above C-fiber heat threshold, but clearly below Aδ-nociceptor heat threshold in order to excite selectively C-fibers without concomitant excitation of Aδ-fibers. Feedback-controlled stepped heat stimuli to 40°C elicited ultralate laser evoked potentials (LEPs) at the vertex in a high proportion of experiments (90{\%}). Estimates of conduction velocity calculated from latency shifts between the hand and forearm sites of ultralate LEPs (2.4 m/s) and of reaction times (2.8 m/s) confirmed mediation of ultralate potentials by unmyelinated nerve fibers (nociceptors and/or warm fibers). The ultralate LEP could be differentiated from resolution of contingent negative variation (CNV), an endogenous potential related to expectation and response preparation, by its scalp topography. Strong heat stimuli of 48°C, which is suprathreshold for most Aδ- and C-fiber nociceptors, elicited the well-known late LEPs mediated by nociceptive Aδ-fibers confirming previous studies. The LEP waveform to strong heat stimuli also contained an ultralate component reminiscent of an ultralate LEP following the late LEP. Ultralate and late LEP had identical scalp topography. In conclusion, the method of temperature-controlled laser heat stimuli allows the selective and reliable examination of Aδ- and C-fiber-mediated afferent pathways and the related cortical processing without the complication of dissociating A-fiber nerve blocks. Copyright (C) 1999 International Association for the Study of Pain. Published by Elsevier Science B.V.",
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AU - Treede, Rolf Detlef

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N2 - Feedback-controlled laser heat was used to stimulate the hairy skin of the hand dorsum and forearm, and heat-evoked cerebral potentials were recorded at midline (Fz, Cz, Pz) and temporal (T3, T4) scalp positions. Based on data from primary afferent electrophysiology a stimulus level (40°C) was chosen, which is above C-fiber heat threshold, but clearly below Aδ-nociceptor heat threshold in order to excite selectively C-fibers without concomitant excitation of Aδ-fibers. Feedback-controlled stepped heat stimuli to 40°C elicited ultralate laser evoked potentials (LEPs) at the vertex in a high proportion of experiments (90%). Estimates of conduction velocity calculated from latency shifts between the hand and forearm sites of ultralate LEPs (2.4 m/s) and of reaction times (2.8 m/s) confirmed mediation of ultralate potentials by unmyelinated nerve fibers (nociceptors and/or warm fibers). The ultralate LEP could be differentiated from resolution of contingent negative variation (CNV), an endogenous potential related to expectation and response preparation, by its scalp topography. Strong heat stimuli of 48°C, which is suprathreshold for most Aδ- and C-fiber nociceptors, elicited the well-known late LEPs mediated by nociceptive Aδ-fibers confirming previous studies. The LEP waveform to strong heat stimuli also contained an ultralate component reminiscent of an ultralate LEP following the late LEP. Ultralate and late LEP had identical scalp topography. In conclusion, the method of temperature-controlled laser heat stimuli allows the selective and reliable examination of Aδ- and C-fiber-mediated afferent pathways and the related cortical processing without the complication of dissociating A-fiber nerve blocks. Copyright (C) 1999 International Association for the Study of Pain. Published by Elsevier Science B.V.

AB - Feedback-controlled laser heat was used to stimulate the hairy skin of the hand dorsum and forearm, and heat-evoked cerebral potentials were recorded at midline (Fz, Cz, Pz) and temporal (T3, T4) scalp positions. Based on data from primary afferent electrophysiology a stimulus level (40°C) was chosen, which is above C-fiber heat threshold, but clearly below Aδ-nociceptor heat threshold in order to excite selectively C-fibers without concomitant excitation of Aδ-fibers. Feedback-controlled stepped heat stimuli to 40°C elicited ultralate laser evoked potentials (LEPs) at the vertex in a high proportion of experiments (90%). Estimates of conduction velocity calculated from latency shifts between the hand and forearm sites of ultralate LEPs (2.4 m/s) and of reaction times (2.8 m/s) confirmed mediation of ultralate potentials by unmyelinated nerve fibers (nociceptors and/or warm fibers). The ultralate LEP could be differentiated from resolution of contingent negative variation (CNV), an endogenous potential related to expectation and response preparation, by its scalp topography. Strong heat stimuli of 48°C, which is suprathreshold for most Aδ- and C-fiber nociceptors, elicited the well-known late LEPs mediated by nociceptive Aδ-fibers confirming previous studies. The LEP waveform to strong heat stimuli also contained an ultralate component reminiscent of an ultralate LEP following the late LEP. Ultralate and late LEP had identical scalp topography. In conclusion, the method of temperature-controlled laser heat stimuli allows the selective and reliable examination of Aδ- and C-fiber-mediated afferent pathways and the related cortical processing without the complication of dissociating A-fiber nerve blocks. Copyright (C) 1999 International Association for the Study of Pain. Published by Elsevier Science B.V.

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KW - Ultralate potentials

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