Premotor Circuits Controlling Eyelid Movements in Conjunction with Vertical Saccades in the Cat: Ii. Interstitial Nucleus of Cajal.
From: Department of Neurology, Southern Illinois University School of Medicine, Springfield, Illinois 21201, USA.
The Journal of comparative neurology
- Publish Date: Feb 2007
- ISSN: 0021-9967
- Volume: 500
- Issue: 4
- Pages: 676-92
- Medium: Print
- Language: English
- Citation (JAMA): Chen Bingzhong, May Paul J, et al. Premotor Circuits Controlling Eyelid Movements in Conjunction with Vertical Saccades in the Cat: Ii. Interstitial Nucleus of Cajal.. J. Comp. Neurol. Feb 2007;500:676-92
Abstract
Vertical saccadic eye movements are accompanied by concurrent eyelid movements in the same direction. The interstitial nucleus of Cajal (InC) controls eye position for vertical eye movements and may also control saccade-related lid position as well. This study investigates whether the InC serves as a premotor center for eyelid saccades, by employing dual-tracer methods in cats to label both the projections of the InC and the motoneurons supplying the levator palpebrae superioris (LPS) muscle, which lie in the caudal central subdivision (CCS) of the oculomotor complex. Injections of biotinylated dextran amine (BDA) into the InC anterogradely labeled axons that terminated bilaterally throughout the CCS and in the oculomotor nuclei proper. Labeled terminals lay in close association with labeled LPS motoneurons, which were retrogradely labeled following injections of wheat germ agglutinin-conjugated horseradish peroxidase (WGA-HRP) into the muscle. Ultrastructural investigation revealed that most terminals contained spherical vesicles and formed asymmetric synaptic contacts with the labeled motoneurons. These results strongly suggest that the InC monosynaptically controls lid movements in conjunction with vertical eye movements, including saccades. To identify the neurons of origin for this pathway, WGA-HRP injections were centered in the CCS. These experiments indicate that lid and eye motoneurons may share a common source of bilateral InC input. Thus, a common vertical position signal may be employed to maintain the lid and eye at appropriate elevations during fixation, such that the lid sits just above the pupil, allowing unobstructed vision, but at the ready to protect the cornea.
Mesh Headings (Keywords): Animals, Cats, Efferent Pathways, Eyelids, Female, Male, Motor Neurons, Movement, Saccades, Tegmentum Mesencephali
Check for Full Text / PubMed Unique Identifier (PMID): 17154251
This abstract is part of PubMed, a service of the U.S. National Library of Medicine. PubMed includes more than 17 million citations from MEDLINE and other life science journals for biomedical articles. See Copyright and Disclaimers.
Linked medical terms appearing on this page are added by Healia to help readers find more information and are not part of the original PubMed document.
The data herein was last updated on July 8th, 2008 and may not reflect the most current and accurate data available from NLM.