Inactivation of the pons blocks medullary-induced muscle tone suppression in the decerebrate cat

Jun Kohyama, Yuan Yang Lai, Jerome M. Siegel

Research output: Contribution to journalArticlepeer-review

24 Citations (Scopus)


The pontomedullary region is responsible for the reduction of muscle activity in rapid-eye-movement sleep and contributes to the control of muscle tone in waking. This study sought to clarify the nature of the interaction between the pontine and medullary reticular formation in mediating muscle tone suppression. The degree of medullary-induced neck muscle tone suppression in the decerebrate cat was assessed before and after microinjection of lidocaine into the pontine reticular formation. Medullary stimulation-induced suppression of neck muscle tone was blocked after pontine lidocaine microinjection. The maximum blockade was observed at 16.6 minutes on average after the injection, and recovery occurred within 45 minutes. We conclude that descending mechanisms from the medulla are not sufficient for the triggering of muscle tone suppression. A two-way interaction between the medulla and pons is hypothesized to play a crucial role in the control of muscle tone.

Original languageEnglish
Pages (from-to)695-699
Number of pages5
Issue number7
Publication statusPublished - 1998 Nov 1
Externally publishedYes


  • Atonia
  • Brainstem
  • Decerebrate cat
  • Lidocaine
  • Muscle tone
  • REM sleep
  • Reverberatory circuit

ASJC Scopus subject areas

  • Clinical Neurology
  • Physiology (medical)


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