Elsevier

Brain Research

Volume 211, Issue 2, 4 May 1981, Pages 427-432
Brain Research

Retractor bulbi muscle responses to oculomotor nerve and nucleus stimulation in the cat

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Abstract

This study demonstratesthe presence of retractor bulbi motoneurons within the oculomotor nucleus which activate muscle units within all 4 slips of the cat retractor bulbi muscle. These muscle units are mechanically different and physiologically separate from retractor bulbi muscle units innervated by the abducens nerve. The retractor bulbi muscle, then, is innervated by two separate pools of motoneurons whose axons are carried in two different cranial nerves. These observations of mechanical properties of retractor bulbi muscle suggest that the oculomotor retractor bulbi motor units may be activated during patterned eye movements.

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Cited by (15)

  • The extraocular motor nuclei: Organization and functional neuroanatomy

    2006, Progress in Brain Research
    Citation Excerpt :

    There was usually leakage from the RBM injections, so it is difficult to estimate how many neurons in abducens and the OMN also supplied the RBM. However, both anatomical and physiological experiments confirm that abducens and oculomotor neurons also innervate the RBM (Crandall et al., 1981; Meredith et al., 1981). In primates, neurons just ventral to, and in, the VI innervate the accessory lateral rectus muscle which is a vestigial form of the retractor bulbi (Chapter 2; Spencer and Porter, 1981; Schnyder, 1984).

  • Biological organization of the extraocular muscles

    2006, Progress in Brain Research
    Citation Excerpt :

    The mammalian retractor bulbi muscle variably has two (mouse), three (dog), or four (rat, rabbit, cat) slips. Innervation of the retractor bulbi exhibits species-specific patterns from branches of the oculomotor and/or abducens nerves (Spencer and Sterling, 1977; Grant et al., 1979, 1981; Crandall et al., 1981; Meredith et al., 1981; Evinger et al., 1987). With the regression of the nictitating membrane to a vestigial plica semilunaris in primates, the retractor bulbi is reduced to a single homologous slip in the monkey, the accessory lateral rectus muscle, which is innervated by the abducens nerve (Spencer and Porter, 1981; Schnyder, 1984).

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Research supported by NIH Grant EY 01442.

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