Types of neurone in and around the intermediate nucleus of the lumbosacral cord

Eccles, John C.; Eccles, Rosamond M.; Lundderg, A.

doi:10.1113/jphysiol.1960.sp006566

Cited by 165 publications

(66 citation statements)

References 42 publications

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“…4) corresponds to the nucleus proprius of the adult (lamina IV of Rexed (1954)), and to the intermediate and dorsomedial zone described by Stelzner (1971) in neonatal rats. Dorsal root fibres make extensive connexions to these areas, including monosynaptic connexions from I a and Ib fibres (Cajal, 191 1;Sprague & Ha, 1964) and in electrophysiological studies in cat spinal cord, the maximum amplitude extracellular response generated by group Ia and Ib fibres of biceps semitendinosus nerve (Eccles et al 1954) was recorded here as were intracellular responses from interneurones (Eccles, Eccles & Lundberg, 1960).…”

Section: Extracellular Field Potentialsmentioning

confidence: 94%

Electrophysiological properties of neonatal rat motoneurones studied in vitro.

Fulton¹,

Walton²

1986

The Journal of Physiology

215

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SUMMARY1. The electroresponsive properties of neonatal lumbar spinal motoneurones were studied using isolated, hemisected spinal cords from neonatal rats aged [3][4][5][6][7][8][9][10][11][12] days. The extracellular and intracellular responses to electrical stimulation of the ventral and dorsal root were studied as well as. the intracellular response to current injection.2. Field potentials recorded in the lateral motor area following electrical stimulation of lumbar ventral roots had a triphasic positive-negative-positive wave form. The negative component did not return to the base line smoothly but exhibited a ' shoulder' where the negativity increased in duration. Following electrical stimulation of the dorsal root, presynaptic field potentials were recorded upon activation of the afferent axons as well as following synaptic activation of interneurones and motoneurones.3. The input resistances of neonatal motoneurones determined from the slope of current-voltage plots were high compared with the adult. The resistance decreased with age with a mean of 18-1 MC for animals 3-5 days old, 8-8 M0 for animals 6-8 days old and 5-4 MC for animals 9-11 days old. Values for the membrane time constant were similar to those in the adult with a mean of 4-5 ms.4. Action potentials elicited by ventral or dorsal root stimulation or by intracellular current injection were marked by a pronounced after-depolarization (a.d.p.) and an after-hyperpolarization (a.h.p.). The amplitude of the a.h.p. varied with that of the a.d.p.5. The amplitude of excitatory post-synaptic potentials (e.p.s.p.s) elicited by electrical stimulation ofthe dorsal root was affected by intracellular current injection. Two types of e.p.s.p.s were distinguished: those with a biphasic reversal (early phase first) and those in which the early phase was unaffected by inward current injection while the later phase was reversed. Unlike in the adult, the reversals could be achieved with low current levels and the amplitude of both types of e.p.s.p. was increased by inward current injection. (b) there is a low maximum firing frequency (near 30 Hz) and (c) the slope of the firing frequency-injected current (f-I) plot has a high gain.8. These results are discussed with respect to previous findings in adult rat and cat and with reference to the properties of the developing nervous and muscular systems.

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Section: Extracellular Field Potentialsmentioning

confidence: 94%

Electrophysiological properties of neonatal rat motoneurones studied in vitro.

Fulton¹,

Walton²

1986

The Journal of Physiology

215

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“…There are now many lines of evidence which suggest that the development of synaptic connexions can be explained only by some such postulate of surface specificity. For example, Group Ia and Ib primary afferent fibres of muscle appear never to make functional synaptic connexions on the same nerve cell, whether this be a motoneurone, an interneurone of the intermediate nucleus, a cell of Clarke's column, or a cell of origin of the ventral spinocerebellar tract (Oscarsson, 1957;Lundberg & Winsbury, 1960;Eccles, Eccles & Lundberg, 1960). Apparently these two types of fibre differ in respect of the surfaces which attract them.…”

Section: Discussionmentioning

confidence: 99%

Monosynaptic excitatory action on motoneurones regenerated to antagonistic muscles

Eccles¹,

Eccles²,

Magni³

1960

The Journal of Physiology

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“…Some interneurones influenced by I a as well as by I b afferents have been found in Rexed's laminae V and VI (Hongo, Jankowska & Lundberg 1966, 1972; see also Eccles, Eccles & Lundberg, 1960) but neither the full pattern of convergence onto them, nor neuronal pathways in which they are interposed have been defined so far. As a first step in the analysis of their function we have now re-investigated the group I input to laminae V-VI interneurones and correlated it with axonal projections of these.…”

Section: Introductionmentioning

confidence: 99%

Common interneurones in reflex pathways from group 1a and 1b afferents of knee flexors and extensors in the cat.

Czarkowska¹,

Jankowska²,

Sybirska³

1981

The Journal of Physiology

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SUMMARY1. Input from group I afferents of knee flexors and extensors to interneurones in Rexed's laminae V-VI in the cat spinal cord was analysed by use of intracellular recording and electrical stimulation ofthe nerves to differentiate between group I a and and I b synaptic actions. The aim was to find out if these interneurones may mediate synaptic actions of both group I a and Ib afferents.2. 28% of the forty-nine neurones analysed were excited by both group Ia and group Ib afferents; 32 % were inhibited by both and 35 % were excited by the one and inhibited by the other. Taking into account all of these actions, input from both subgroups of group I afferents was found in nearly 60 % of neurones. Most were also excited and/or inhibited by group I afferents of ankle and toe extensors.3. Selective (excitatory and/or inhibitory) input from Ia afferents was found in 18 % and from I b afferents in 22 % of the neurones.4. Excitation was evoked from I a afferents of either knee flexors or extensors but not from both. In several of the neurones Ia i.p.s.p.s were, however, evoked from both posterior biceps-semitendinosus and quadriceps.5. Intracellular staining with horseradish peroxidase revealed axonal projections of laminae V-VI interneurones to motor nuclei as well as to the intermediate zone, ipsilateral as well as contralateral. No correlation was found between patterns ofinput from group I afferents and axonal projections, and interneurones co-excited by I a and I b afferents were among those with different axonal projections.

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Types of neurone in and around the intermediate nucleus of the lumbosacral cord

Cited by 165 publications

References 42 publications

Electrophysiological properties of neonatal rat motoneurones studied in vitro.

Electrophysiological properties of neonatal rat motoneurones studied in vitro.

Monosynaptic excitatory action on motoneurones regenerated to antagonistic muscles

Common interneurones in reflex pathways from group 1a and 1b afferents of knee flexors and extensors in the cat.

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