Vertex-recorded, rather than primary somatosensory cortex-recorded, somatosensory-evoked potentials signal unpleasantness of noxious stimuli in the rat

Peter J Stienen, Hugo van Oostrom, Ruud van den Bos, Harry N M de Groot, Ludo J Hellebrekers

    Research output: Contribution to journalArticle (Academic Journal)peer-review

    11 Citations (Scopus)

    Abstract

    In the present study, we investigated in the rat whether vertex- or primary somatosensory cortex-recorded somatosensory-evoked potentials (Vx-SEP/SI-SEP, respectively) signal unpleasantness of noxious stimuli. Therefore, initially we characterised fentanyl effects (0, 20, 40 or 50 microg/kg/h) on somatosensory and auditory processing by recording Vx-/SI-SEPs and vertex- and primary auditory cortex-recorded auditory-evoked potentials (Vx-/AI-AEPs, respectively). Subsequently, in a separate experiment, the animals were subjected to a Pavlovian fear-conditioning paradigm. The noxious stimuli applied to evoke Vx-/SI-SEPs (unconditioned stimulus (US)) were paired to a tone (conditioned stimulus (CS)) under 'steady state' conditions of 0, 20, 40 or 50 microg/kg/h fentanyl. Vx-/SI-SEPs were recorded simultaneously during these trials. After CS-US presentation, CS-induced fear-conditioned behaviour was analysed in relation to the SEPs recorded during CS-US presentation and the AEPs recorded in the first experiment. While the SI-SEP and AI-AEP were minimally but significantly affected, fentanyl dose-dependently decreased the Vx-SEP and Vx-AEP. The decrease of the Vx-SEP and Vx-AEP was parallelled by the dose-dependent decrease of the amount of CS-induced fear-conditioned behaviour. These results suggest that the dose-dependent decrease of the Vx-SEP amplitude, rather than of the SI-SEP, indicates that the US was experienced as less unpleasant. Next to an altered US processing, altered CS processing contributed to the decrease of the amount of CS-induced fear-conditioned behaviour as indicated by the dose-dependent decrease of the Vx-AEP.

    Original languageEnglish
    Pages (from-to)203-12
    Number of pages10
    JournalBrain Research Bulletin
    Volume70
    Issue number3
    DOIs
    Publication statusPublished - 31 Jul 2006

    Keywords

    • Analgesics, Opioid
    • Animals
    • Conditioning, Classical
    • Dose-Response Relationship, Drug
    • Electroencephalography
    • Evoked Potentials, Auditory
    • Evoked Potentials, Somatosensory
    • Fear
    • Fentanyl
    • Male
    • Pain
    • Rats
    • Rats, Wistar

    Fingerprint Dive into the research topics of 'Vertex-recorded, rather than primary somatosensory cortex-recorded, somatosensory-evoked potentials signal unpleasantness of noxious stimuli in the rat'. Together they form a unique fingerprint.

    Cite this