Tail-flick related activity in medullospinal neurons

Horacio Vanegas, Nicholas Barbaro, Howard L. Fields

Research output: Contribution to journalArticle

121 Citations (Scopus)

Abstract

Using the classification system of Fields et al.16 131 neurons in the rostral ventromedial medulla (RVM) of lightly anesthetized rats were divided into 3 groups according to their response during tail-flick (TF) testing: those with an abrupt increase in activity prior to TF (on-cells); those with a sudden pause in activity prior to TF (off-cells); those with no change in activity prior to TF (neutral cells). Collision testing was performed using a cervical spinal cord stimulating electrode to determine whether these neurons projected to the cord. Conduction velocities were determined for all cord-projecting neurons. All 3 cell types projected to the cord and approximately 38% of cord-projecting neurons were flick-related (off-or on-cells). All projecting neurons were within or immediately adjacent to the nucleus raphe magnus. The mean conduction velocity of on-cell axons (17.7 m/s) was significantly greater than that of off-cell axons (10.7 m/s) and neutral cell axons (12.4 m/s). Conduction velocities for all cells were within the range for myelinated axons. These findings support the hypothesis16 that off- and on-cells in the RVM play a significant role in pain modulation at the spinal cord level.

Original languageEnglish (US)
Pages (from-to)135-141
Number of pages7
JournalBrain Research
Volume321
Issue number1
DOIs
StatePublished - Oct 29 1984
Externally publishedYes

Fingerprint

Tail
Neurons
Axons
Spinal Cord
Electrodes
Pain

Keywords

  • analgesia
  • collision test
  • nucleus raphe magnus
  • rat
  • spinal cord

ASJC Scopus subject areas

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

Cite this

Tail-flick related activity in medullospinal neurons. / Vanegas, Horacio; Barbaro, Nicholas; Fields, Howard L.

In: Brain Research, Vol. 321, No. 1, 29.10.1984, p. 135-141.

Research output: Contribution to journalArticle

Vanegas, H, Barbaro, N & Fields, HL 1984, 'Tail-flick related activity in medullospinal neurons', Brain Research, vol. 321, no. 1, pp. 135-141. https://doi.org/10.1016/0006-8993(84)90689-9
Vanegas, Horacio ; Barbaro, Nicholas ; Fields, Howard L. / Tail-flick related activity in medullospinal neurons. In: Brain Research. 1984 ; Vol. 321, No. 1. pp. 135-141.
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