The role of extraocular muscle proprioception in visual processing and neural control of eye and eye/head movements has remained obscure. In recent years, some fundamental structural characteristics of the extraocular muscle sensory apparatus have been elucidated to the extent that the peripheral receptor apparatus, location of first-order sensory neuron somata, and course and central termination sites of primary sensory neurons are well defined. Furthermore, compelling anatomical and physiological evidence for the interaction of eye and neck muscle proprioceptive signals, potentially functioning in the coordination of eye/head movements, has been obtained. As yet, we have only the most primitive notions regarding the functional role mediated by sensory signals arising from the muscles that move the eyes. While the most profound results of sensory denervation, to date, appear to involve the visual sensory system, only recently have we made any progress into understanding how proprioception is utilized by the oculomotor system. The application represents a continuation of our efforts to determine the anatomical substrate for and functional significance of extraocular muscle proprioception. We are now in the position to apply correlated anatomical and physiological techniques to the problem of extraocular muscle proprioception.
The specific aims of studies to be undertaken in the next project period are directed toward: (a) description of the synaptic relationship of first-order extraocular muscle sensory neurons to second-order neurons in the cuneate nucleus, and of the pathways for subsequent distribution of proprioceptive information and (b) characterization of the nature and precision of signals arising from the eye muscle proprioceptive apparatus by recording from single units in the cuneate nucleus of the chronic alert monkey trained to perform eye movement tasks. Taken together, these studies represent a correlated morphophysiological approach toward understanding what has been a relatively neglected component of the oculomotor and visual systems.

Agency
National Institute of Health (NIH)
Institute
National Eye Institute (NEI)
Type
Research Project (R01)
Project #
5R01EY005464-06
Application #
3260549
Study Section
Visual Sciences B Study Section (VISB)
Project Start
1984-07-01
Project End
1989-10-31
Budget Start
1989-07-01
Budget End
1989-10-31
Support Year
6
Fiscal Year
1989
Total Cost
Indirect Cost
Name
University of Mississippi Medical Center
Department
Type
Schools of Medicine
DUNS #
928824473
City
Jackson
State
MS
Country
United States
Zip Code
39216
May, P J; Porter, J D (1998) The distribution of primary afferent terminals from the eyelids of macaque monkeys. Exp Brain Res 123:368-81
Horn, A K; Porter, J D; Evinger, C (1993) Botulinum toxin paralysis of the orbicularis oculi muscle. Types and time course of alterations in muscle structure, physiology and lid kinematics. Exp Brain Res 96:39-53
Porter, J D; Baker, R S (1992) Prenatal morphogenesis of primate extraocular muscle: neuromuscular junction formation and fiber type differentiation. Invest Ophthalmol Vis Sci 33:657-70
May, P J; Porter, J D; Gamlin, P D (1992) Interconnections between the primate cerebellum and midbrain near-response regions. J Comp Neurol 315:98-116
May, P J; Porter, J D (1992) The laminar distribution of macaque tectobulbar and tectospinal neurons. Vis Neurosci 8:257-76
Porter, J D; Strebeck, S; Capra, N F (1991) Botulinum-induced changes in monkey eyelid muscle. Comparison with changes seen in extraocular muscle. Arch Ophthalmol 109:396-404
Porter, J D; Donaldson, I M (1991) The anatomical substrate for cat extraocular muscle proprioception. Neuroscience 43:473-81
May, P J; Hartwich-Young, R; Nelson, J et al. (1990) Cerebellotectal pathways in the macaque: implications for collicular generation of saccades. Neuroscience 36:305-24
Porter, J D; Burns, L A; May, P J (1989) Morphological substrate for eyelid movements: innervation and structure of primate levator palpebrae superioris and orbicularis oculi muscles. J Comp Neurol 287:64-81
Porter, J D; Burns, L A; McMahon, E J (1989) Denervation of primate extraocular muscle. A unique pattern of structural alterations. Invest Ophthalmol Vis Sci 30:1894-908

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