Role of corticobulbar projection neurons in cortically induced rhythmical masticatory jaw-opening movement in the guinea pig

The role of the pyramidal tract in the induction of the rhythmical masticatory activity of the anterior digastric motoneurons by repetitive stimulation of the cortical masticatory area was studied in the ketamine-anesthetized guinea pig

S. Nozaki

2017

Scholarcy highlights

  • The role of the pyramidal tract in the induction of the rhythmical masticatory activity of the anterior digastric motoneurons by repetitive stimulation of the cortical masticatory area was studied in the ketamine-anesthetized guinea pig
  • Unilateral section of the PT at the pontine level abolished the RMA in the digastric EMG induced by repetitive stimulation of the ipsilateral CMA, while that induced by the contralateral CMA stimulation was not affected by the PT section
  • The threshold of repetitive PT stimulation for induction of the RMA of the digastric EMG was much higher at the levels caudal to the facial nucleus than that at more rostral levels, and no RMA was induced by the PT stimulation at the caudal bulbar levels even at the supramaximal intensities for RMA induction of the PT stimulation at more rostral levels
  • Single shocks applied to the CMA evoked a negative field potential in the medial bulbar reticular formation mainly on the contralateral side after a monosynaptic latency, which was largest in amplitude in the region including the most dorsal portion of the nucleus reticularis paragigantocellularis and the area dorsally adjacent to it
  • Intracellular recording from neurons in the dPGC demonstrated that neurons were located in the dPGC that responded with EPSPs after a monosynaptic latency to single shocks applied to the contralateral CMA and with antidromic spike potentials to stimulation of the oral portion of the ipsilateral GC
  • The number and density of the labeled cells on the contralateral side far exceeded those on the ipsilateral side.(ABSTRACT TRUNCATED AT 400 WORDS)

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