Chonnam Med J.  2001 Mar;37(1):55-61.

Reflex Actions of the Semicircular Canals on the Rectus Capitis Anterior Major and the Rectus Capitis Posterior Major Muscles in Cats

• Jeong HS
• Park JS

Abstract

Electromyographic responses of the rectus capitis anterior major and the rectus capitis posterior major muscles to the stimulations of the semicircular canal nerves were observed to explore the functional relationships between the canals and these axial muscles. The rectus capitis anterior major muscle was inhibited by stimulating the ipsilateral horizontal canal nerve and excited by stimulating the contralateral horizontal canal nerve. The rectus capitis posterior major muscle was inhibited by stimulating the ipsilateral horizontal canal nerve and excited by stimulating the contralateral horizontal canal nerve. The rectus capitis anterior major and the rectus capitis posterior major muscles were inhibited by stimulating the ipsilateral anterior canal nerve. These responses were reversed by stimulation of the functionally paired posterior canal nerves. Based on these results, we formulated showing the functional connections between the receptor canals and the effector muscles for a schematic diagram vestibulocollic reflexes. The diagram revealed that the excitatory neural pathways from the vestibular nucleus to the cervical motoneurons were crossed to the opposite side, whereas the inhibitory pathways from the nucleus to these axial motoneurons were uncrossed.

Keyword

Vestibulocollic reflex; Rectus capitis anterior major; Rectus capitis posterior major

MeSH Terms

Animals
Cats*
Muscles*
Neural Pathways
Reflex*
Semicircular Canals*