Segmental reflex inputs to motoneurons innervating dorsal neck musculature in the cat
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The responses to Stimulation of upper cervical muscle and cutaneous afferents were studied in motoneurons innervating splenius, complexus, and biventer cervicis dorsal neck muscles of cats. Motoneurons innervating complexus and biventer cervicis fibers, which are in the deeper, longitudinally oriented muscles, were monosynaptically excited by ipsilateral Group I afferents from each of these muscles, but they did not receive significant input from splenius Group I afferents. Likewise, splenius motoneurons were not monosynaptically excited by ipsilateral afferents from complexus and biventer cervicis. Stimulation of ipsilateral cutaneous afferents produced predominant excitation in splenius motoneurons, predominant inhibition in biventer cervicis motoneurons, and inhibition or mixed responses in complexus motoneurons.
None of the neck motoneurons studied showed postsynaptic potentials following single or multiple shock stimulation of contralateral muscle nerves at stimulus intensities expected to excite exclusively Group I afferents. Higher intensity stimulation of contralateral muscle afferents, as well as fibers in the greater auricular nerves, produced predominant inhibition in all three neck motoneuron pools.
Segmentally-excited afferents to neck motoneurons, like those from supraspinal systems, appear to evoke different patterns of synaptic responses in splenius motoneurons than they do in motoneurons innervating fibers in the deeper, longitudinally oriented complexus and biventer cervicis muscles.
Key wordsNeck motoneurons Upper-cervical reflexes
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- Abrahams, V.C., Richmond, F.J.R., Rose, P.K.: Absence of monosynaptic reflex in dorsal neck muscles of the cat. Brain Res. 92, 130–131 (1975)Google Scholar
- Anderson, M.E., Yoshida, M., Wilson, V.J.: Influence of superior colliculus on cat neck motoneurons. J. Neurophysiol. 34, 898–907 (1971)Google Scholar
- Bruggencate, G. ten, Lundberg, A.: Facilitatory interaction in transmission to motoneurones from vestibulospinal fibers and contralateral primary afferents. Exp. Brain Res. 19, 248–270 (1970)Google Scholar
- Burke, R.E.: Motor unit types of cat triceps surae muscle. J. Physiol. (Lond.) 193, 141–160 (1967)Google Scholar
- Burke, R.E., Jankowska, E., ten Bruggencate, G.: A comparison of peripheral and rubrospinal synaptic input to slow and fast twitch motor units of triceps surae. J. Physiol. (Lond.) 207, 709–732 (1970)Google Scholar
- Burke, R.E., Levine, D.M., Tsairis, P., Zajac, F.E.: Physiological types and histochemicalprofiles in motor units of the cat gastrocnemius. J. Physiol. (Lond.) 234, 723–748 (1973)Google Scholar
- Cooper, S., Daniel, P.M.: Muscle spindles in man: their morphology in the lumbricals and the deep muscles of the neck. Brain Res. 86, 563–594 (1963)Google Scholar
- Eccles, J.C., Eccles, R.M., Lundberg, A.: Synaptic actions on motoneurons in relation to the two components of the Group I muscle afferent volley. J. Physiol. (Lond.) 136, 525–546 (1957)Google Scholar
- Eccles, J.C., Eccles, R.M., Lundburg, A.: The action potentials of the alpha motoneurons supplying fast and slow muscles. J. Physiol. (Lond.) 142, 275–291 (1958)Google Scholar
- Holmqvist, B.: Crossed spinal reflex actions evoked by volleys in somatic afferents. Acta physiol. scand. 52, Suppl. 181 (1961)Google Scholar
- Kuno, M., Miyata, Y., Munoz-Martinez, E.J.: Differential reaction of fast and slow α-motoneurons to axotomy. J. Physiol. (Lond.) 240, 725–739 (1974)Google Scholar
- Li, C.L., Bak, A.: Excitability characteristics of the A- and C-fibers in a peripheral nerve. Exp. Neurol. 50, 67–79 (1976)Google Scholar
- Lloyd, D.P.C., Wilson, V.J.: Functional organization in the terminal segments of the spinal cord with a consideration of central excitatory and inhibitory latencies in monosynaptic reflex systems. J. gen. Physiol. 42, 1219–1231 (1959)Google Scholar
- Perl, E.R.: Crossed reflex effects evoked by activity in myelinated afferent fibers of muscle. J. Neurophysiol. 21, 101–112 (1958)Google Scholar
- Phillips, C.G.: The Ferrier Lecture, 1968. Motor apparatus of the baboon's hand. Proc. roy. Soc. B 173, 141–174 (1969)Google Scholar
- Reighard, J., Jennings, H.S.: Anatomy of the Cat (3rd ed.). New York: Holt, Rinehart and Winston 1961Google Scholar
- Richmond, F.J.R., Abrahams, V.C.: Morphology and distribution of muscle spindles in dorsal muscles of the cat neck. J. Neurophysiol. 38, 1322–1339 (1975a)Google Scholar
- Richmond, F.J.R., Abrahams, V.C.: Morphology and enzyme histochemistry of dorsal muscles of the cat neck. J. Neurophysiol. 38, 1312–1321 (1975b)Google Scholar
- Vallbo, Å.B.: Muscle spindle responses at the onset of isometric voluntary contractions in man. Time differences between fusimotor and skeletomotor effects. J. Physiol. (Lond.) 218, 405–431 (1971)Google Scholar
- Vallbo, Å.B.: Muscle spindle afferent discharge from resting and contracting muscles in normal human subjects. In: New Developments in Electromyography and Clinical Neurophysiology (ed. J. Desmedt), Vol. 3, pp. 251–262 (1973)Google Scholar
- Wilson, V.J., Maeda, M.: Connections between semicircular canals and neck motoneurons in the cat. J. Neurophysiol. 37, 346–357 (1974)Google Scholar
- Wilson, V.J., Yoshida, M.: Comparison of effects of Deiters' nucleus and medial longitudinal fasciculus on neck, forelimb, and hindlimb motoneurons. J. Neurophysiol. 32, 743–758 (1969a)Google Scholar
- Wilson, V.J., Yoshida, M.: Monosynaptic inhibition of neck motoneurons by the medial vestibular nucleus. Exp. Brain Res. 9, 365–380 (1969b)Google Scholar