Dynamic changes of touch- and laser heat-evoked field potentials of primary somatosensory cortex in awake and pentobarbital-anesthetized rats

Fu Zen Shaw, Ruei Feng Chen, Chen Tung Yen

Research output: Contribution to journalArticle

45 Citations (Scopus)

Abstract

In this investigation, changes of mechanical- (MEP) and laser-evoked potentials (LEP) in rat primary somatosensory cortex during the course of pentobarbital (PB) anesthesia were examined. Temporal analysis of changes in the magnitude and latency of MEP and LEP, EEG activity, gross motor behaviors, and the tail flick response following laser stimulation before, during, and after PB administration (50 mg/kg, i.p.) was performed and correlated in chronically implanted rats. During the wakeful condition, there were two major cortical components each following mechanical stimulation (MEP1 and MEP2, n = 17) and laser stimulation (LEP1 and LEP2, n = 10), respectively. After PB administration, the positive peak in MEP1 was enhanced, and all other components disappeared. These components returned with different time courses. Two hours after PB administration, when the rat had spontaneous movements and flexor reflexes, LEP2 showed reversed polarity. MEP2 returned gradually 3 h after PB administration when the rat regained its ability to execute coordinated movements. After 4 h, LEP1 began to reappear and LEP2 returned to its negative polarity. We found that PB facilitated Aβ fiber-related cortical evoked potential (MEP1), while differentially inhibited Aδ and C fiber-related components (MEP2, LEP1 and LEP2). Characterization of these anesthesia-induced changes in cortical output may be useful in studying the neural basis of tactile and pain sensations.

Original languageEnglish
Pages (from-to)105-115
Number of pages11
JournalBrain Research
Volume911
Issue number2
DOIs
Publication statusPublished - 2001 Aug 24

All Science Journal Classification (ASJC) codes

  • Neuroscience(all)
  • Molecular Biology
  • Clinical Neurology
  • Developmental Biology

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