Chemo-somatosensory evoked potentials: a sensitive tool to assess conditioned pain modulation?

Kunz, M., Mohammadian, P., Renner, B., Roscher, S., Kobal, G. & Lautenbacher, S., Jun-2014, In : Somatosensory & Motor Research. 31, 2, p. 100-10 11 p.

Research output: Contribution to journalArticleAcademicpeer-review

  • Miriam Kunz
  • Parvaneh Mohammadian
  • Bertold Renner
  • Stephan Roscher
  • Gerd Kobal
  • Stefan Lautenbacher

UNLABELLED: Abstract Background: Chemo-somatosensory evoked potentials (CSSEPs) elicited by chemical stimulation (CO₂ gas) of the nasal mucosa have been shown to be sensitive enough to pick up even weak analgesic effects. With the present study we wanted to investigate whether CSSEPs are also a sensitive tool to capture endogenous pain inhibitory mechanisms elicited by conditioned pain modulation (CPM; where a first conditioning stimulus reduces the sensitivity for a second test stimulus) with a conditioning stimulus of rather low noxious load.

METHODS: Seventeen healthy participants were tested for CPM effects (conditioning stimulus: tonic heat pain with intensities around the pain threshold induced via a thermode; test stimulus: chemonasal stimulation (73% and 78% CO₂)) on CSSEPs and on self-report ratings.

RESULTS: We found significant CPM effects in the CSSEPS, with reduced amplitudes and prolonged latencies at several electroencephalogram (EEG) recording positions when using the lower CO₂ concentration (73% CO₂). In contrast to the visible inhibitory effects on the CSSEPs, subjective ratings of the test stimulus did not reflect CPM action.

DISCUSSION: The experimental pain model using CO₂ stimuli to elicit CSSEPs proved to be sensitive enough to capture weak CPM effects elicited by a conditioning stimulus of rather low noxious load. The usage of such mild noxious conditioning stimuli-in contrast to stimuli of higher noxious load (e.g., cold pressor test)-has the advantage that the activation of other types of pain inhibitory mechanisms in parallel (like attentional distraction, stress-induced analgesia) can be avoided.

Original languageEnglish
Pages (from-to)100-10
Number of pages11
JournalSomatosensory & Motor Research
Issue number2
Publication statusPublished - Jun-2014


  • Adult, Carbon Dioxide, Conditioning (Psychology), Electroencephalography, Evoked Potentials, Somatosensory, Female, Humans, Male, Pain, Pain Measurement, Pain Threshold, Psychophysics, Young Adult

ID: 29188040