Number and distribution of stapedius motoneurons in cats
Article first published online: 9 OCT 2004
Copyright © 1985 Alan R. Liss, Inc.
Journal of Comparative Neurology
Volume 232, Issue 1, pages 43–54, 1 February 1985
How to Cite
Joseph, M. P., Guinan, J. J., Fullerton, B. C., Norris, B. E. and Kiang, N. Y. S. (1985), Number and distribution of stapedius motoneurons in cats. J. Comp. Neurol., 232: 43–54. doi: 10.1002/cne.902320105
- Issue published online: 9 OCT 2004
- Article first published online: 9 OCT 2004
- Manuscript Accepted: 5 SEP 1984
- middle-ear muscles;
- facial nerve;
- stapedius neurons;
- acoustic reflexes
Cell bodies of stapedius motoneurons were identified by retrograde transport of horseradish peroxidase (HRP) following injections into the stapedius muscle. Large injections were made in an attempt to label all stapedius motoneurons. To control for labeling of non-stapedial neurons resulting from spread of HRP, we determined the locations of brainstem neurons labeled by HRP applied to the facial nerve, the chorda tympani nerve, the auricular branch of the vagus nerve, the tensor tympani muscle, and the cochlea. In three cats analyzed in detail, 1,133–1,178 neurons projecting to the stapedius muscle were identified. Arguments are given which suggest that in these three cats all stapedius motoneurons were labeled. The labeled stapedius neurons may all be motoneurons because they all stain positively for acetylcholinesterase and have medium–coarse Nissl bodies. Most stapedius motoneurons were located around the motor nucleus of the facial nerve. Stapedius motoneurons were also found near the descending limb of the facial-nerve root, in the peri-olivary neuropil, and in the reticular formation with the ascending fibers of the facial-nerve root.