Midbrain stimulation inhibits tail-flick only at currents sufficient to excite rostral medullary neurons

Horacio Vanegas, Nicholas M. Barbaro, Howard L. Fields

Research output: Contribution to journalArticle

70 Scopus citations


The effects of midbrain electrical stimulation on the activity of tail-flick (TF) related neurons in the rostral ventromedial medulla (RVM) were studied. Neurons whose activity either decreased (off-cells) or increased (on-cells) immediately prior to TF were examined. Of 31 off- and on-cells, 26 (84%) showed increased activity during midbrain stimulation sufficient to suppress the TF. Furthermore, in 21 of these cells, the threshold for activation was identical to the threshold for TF suppression, and in the other 5 cells the threshold difference was ≤5 μA. This study provides evidence that off- and on-cells in the RVM mediate the antinociceptive actions of midbrain stimulation.

Original languageEnglish (US)
Pages (from-to)127-133
Number of pages7
JournalBrain research
Issue number1
StatePublished - Oct 29 1984



  • analgesia
  • nucleus raphe magnus
  • periaqueductal gray
  • rat
  • stimulation-produced analgesia
  • tail-flick test

ASJC Scopus subject areas

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

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