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Integration in trigeminal premotor interneurones in the cat

Integration in trigeminal premotor interneurones in the cat 221 84 84 1 1 K. Å. Olsson K.-G. Westberg Department of Physiology University of Umeå S-901 87 Umeå Sweden Department of Prosthetic Dentistry University of Umeå S-901 87 Umeå Sweden Department of Endodontics University of Umeå S-901 87 Umeå Sweden Department of Physiology, Prosthetic Dentistry University of Umeå S-901 87 Umeå Sweden Summary Seventy-one ( n = 71) premotor interneurones have been localized by extracellular recordings within the subnucleus- γ of the oral nucleus of the spinal trigeminal tract (NVspo- γ ) in nineteen chloralose anaesthetized cats. The neurons were antidromically activated by microstimulation (minimum = 3μA) applied to the digastric motoneurone subnucleus of the trigeminal motor nucleus. Fifty-one ( n = 51) of the interneurones were discharged from the ipsiand nineteen ( n = 19) from the contralateral digastric subnucleus. One neurone out of four tested was antidromically activated from both stimulation sites suggesting a bifurcated axon. The identified premotor neurones had a unique convergence profile of oral and perioral primary afferents. Latency calculations indicated that at least 55% of these interneurones were monosynaptically activated by low stimulus strength applied to the inferior alveolar (minimum=1.0 T) and/or the lingual nerve (minimum=1.0 T). The thresholds for evoking the neuronal discharges coincided statistically with those required to evoke a jaw opening reflex response by stimulation of the same nerves. It is suggested that the specific group of NVspo- γ interneurones under different contexts mediates the disynaptic reflex and participates in the centrally and reflexly evoked “patterning” adjustments of the digastric jaw opening motoneurones during ongoing jaw movements. A companion paper reports the convergence of descending cortical, tectal and ascending cervical inputs, as well as of oro-facial and neck primary afferent inputs onto an unselected population of interneurones in the NVspo- γ (Westberg and Olsson 1991). http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Experimental Brain Research Springer Journals

Integration in trigeminal premotor interneurones in the cat

Olsson, K.; Westberg, K.-G.
Experimental Brain Research , Volume 84 (1) – Mar 1, 1991
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References (47)

Publisher
Springer Journals
Copyright
Copyright © 1991 by Springer-Verlag
Subject
Biomedicine; Neurosciences; Neurology
ISSN
0014-4819
eISSN
1432-1106
DOI
10.1007/BF00231766
Publisher site
See Article on Publisher Site

Abstract

221 84 84 1 1 K. Å. Olsson K.-G. Westberg Department of Physiology University of Umeå S-901 87 Umeå Sweden Department of Prosthetic Dentistry University of Umeå S-901 87 Umeå Sweden Department of Endodontics University of Umeå S-901 87 Umeå Sweden Department of Physiology, Prosthetic Dentistry University of Umeå S-901 87 Umeå Sweden Summary Seventy-one ( n = 71) premotor interneurones have been localized by extracellular recordings within the subnucleus- γ of the oral nucleus of the spinal trigeminal tract (NVspo- γ ) in nineteen chloralose anaesthetized cats. The neurons were antidromically activated by microstimulation (minimum = 3μA) applied to the digastric motoneurone subnucleus of the trigeminal motor nucleus. Fifty-one ( n = 51) of the interneurones were discharged from the ipsiand nineteen ( n = 19) from the contralateral digastric subnucleus. One neurone out of four tested was antidromically activated from both stimulation sites suggesting a bifurcated axon. The identified premotor neurones had a unique convergence profile of oral and perioral primary afferents. Latency calculations indicated that at least 55% of these interneurones were monosynaptically activated by low stimulus strength applied to the inferior alveolar (minimum=1.0 T) and/or the lingual nerve (minimum=1.0 T). The thresholds for evoking the neuronal discharges coincided statistically with those required to evoke a jaw opening reflex response by stimulation of the same nerves. It is suggested that the specific group of NVspo- γ interneurones under different contexts mediates the disynaptic reflex and participates in the centrally and reflexly evoked “patterning” adjustments of the digastric jaw opening motoneurones during ongoing jaw movements. A companion paper reports the convergence of descending cortical, tectal and ascending cervical inputs, as well as of oro-facial and neck primary afferent inputs onto an unselected population of interneurones in the NVspo- γ (Westberg and Olsson 1991).

Journal

Experimental Brain Research – Springer Journals

Published: Mar 1, 1991

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