The objective of this research program is to increase our understanding of how the central nervous system controls and coordinates activity in the jaw muscles for the production of complex motor behaviors such as chewing. In humans, single motor unit electromyography will be used to study the function of the muscles of mastication. At various times during the production of precisely controlled voluntary tasks stimuli will be delivered to trigeminal sensory receptors to determine the effects of this peripheral input on the centrally programmed movements. Analysis of recruitment patterns, contractile properties and spike train characteristics of single motor units will be used to determine the mechanisms by which the nervous system codes for the sequence and intensity of contraction of the various muscles of mastication. These techniques will be used as well to determine the role of the nervous system in the establishment of the 'rest' postion of the mandible. Patients with the myofascial pain-dysfunction syndrome will also be studied. The characteristics of muscle function established in normal subjects will be compared with those of patients with this syndrome in order to establish the nature of the neuromuscular disorder which leads to the motor disability. Neurophysiological studies will focus on the use of the guinea pig as an experimental model for study of the interaction of the central nervous system pattern generators responsible for producing rhythmic masticatory movements with the reflex effects of peripheral feedback which results from those movements. Intracellular recording in motoneurons which control the muscles of mastication will be obtained during rhythmic masticatory movements and chewing behavior and will permit analysis of inhibitory and subthreshold excitatory events not observable with any other method. This technique is extremely useful in the study of motor control since the membrane characteristics of motoneurons innervating a particular muscle can be observed during the actual performance of behaviors in which that muscle is involved.

Agency
National Institute of Health (NIH)
Institute
National Institute of Dental & Craniofacial Research (NIDCR)
Type
Research Project (R01)
Project #
5R01DE004166-18
Application #
3218984
Study Section
Neurology B Subcommittee 1 (NEUB)
Project Start
1978-07-01
Project End
1989-06-30
Budget Start
1987-07-01
Budget End
1988-06-30
Support Year
18
Fiscal Year
1987
Total Cost
Indirect Cost
Name
University of California Los Angeles
Department
Type
Schools of Dentistry/Oral Hygn
DUNS #
119132785
City
Los Angeles
State
CA
Country
United States
Zip Code
90095
Gerstner, G E (1996) Haloperidol affects guinea pig chewing burst durations. Brain Behav Evol 48:94-102
Hsiao, C F; Chandler, S H (1995) Characteristics of a fast transient outward current in guinea pig trigeminal motoneurons. Brain Res 695:217-26
Inoue, T; Chandler, S H; Goldberg, L J (1994) Neuropharmacological mechanisms underlying rhythmical discharge in trigeminal interneurons during fictive mastication. J Neurophysiol 71:2061-73
Chandler, S H; Hsaio, C F; Inoue, T et al. (1994) Electrophysiological properties of guinea pig trigeminal motoneurons recorded in vitro. J Neurophysiol 71:129-45
Gerstner, G E; Goldberg, L J (1991) Genioglossus EMG activity during rhythmic jaw movements in the anesthetized guinea pig. Brain Res 562:79-84
Chandler, S H; Turman Jr, J; Salem, L et al. (1990) The effects of nanoliter ejections of lidocaine into the pontomedullary reticular formation on cortically induced rhythmical jaw movements in the guinea pig. Brain Res 526:54-64
Gurahian, S M; Chandler, S H; Goldberg, L J (1989) Intracellular analysis of trigeminal motoneuron rhythmical activity during stimulation of pontomedullary reticular formation in anesthetized guinea pig. J Neurophysiol 62:1225-36
Gerstner, G E; Goldberg, L J; De Bruyne, K (1989) Angiotensin II-induced rhythmic jaw movements in the ketamine-anesthetized guinea pig. Brain Res 478:233-40
Gerstner, G E; Goldberg, L J (1989) An analysis of mandibular movement trajectories and masticatory muscle EMG activity during drinking in the guinea pig. Brain Res 479:6-15
Chandler, S H; Goldberg, L J (1988) Effects of pontomedullary reticular formation stimulation on the neuronal networks responsible for rhythmical jaw movements in the guinea pig. J Neurophysiol 59:819-32

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