A relay for input from group II muscle afferents in sacral segments of the cat spinal cord.

Jankowska, E.; Riddell, John S.

doi:10.1113/jphysiol.1993.sp019693

Cited by 34 publications

(58 citation statements)

References 51 publications

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“…The interneurones were located in the dorsal horn, predominantly in the lateral half of laminae IV and V of Rexed (1954), as indicated in Fig. lA-C (Jankowska & Riddell, 1993b). In accordance with these observations, when several (7-10) different ipsilateral muscle nerves were investigated for their effects on sacral interneurones, group II afferents of the PBST nerve appeared to be the main source of input.…”

Section: Methods Preparationsupporting

confidence: 62%

“…We have recently reported that neurones relaying segments, several types of neurones have input from group information from group II muscle afferents are located not II afferents; these include last order interneurones with only rostral, as previously found by Edgley & Jankowska excitatory and inhibitory actions on motoneurones (1987a), but also caudal to the lumbosacral enlargement (Cavallari, Edgley & Jankowska, 1987), other interneurones (Jankowska & Riddell, 1993b), i.e. both in midlumbar and (Edgley & Jankowska, 1987b) and ascending tract neurones in sacral segments of the spinal cord.…”

mentioning

confidence: 91%

“…The animals' core temperature was maintained at 37-38 0C and that in the paraffin pools at 35-37 0C. The same cats were also used for the studies reported by Jankowska & Riddell (1993b). A number of left hindlimb peripheral nerves were dissected and mounted on electrodes.…”

Section: Methods Preparationmentioning

confidence: 99%

“…Electrode penetrations were made between blood vessels covering the surface of the dorsal columns on the left side. Selection of the region in which to make electrode penetrations was guided by the rostrocaudal distribution of the largest cord dorsum potentials evoked by group II afferents of the PBST nerve which are associated with the largest group II field potentials at the level of Onuf's nucleus (Jankowska & Riddell, 1993b).…”

Section: Methods Preparationmentioning

confidence: 99%

“…(iii) To what extent do the properties of group II-activated neurones in the sacral segments resemble or differ from those of midlumbar group II neurones? Preliminary observations have been published in abstract form (Jankowska & Riddell, 1992, 1993a.…”

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confidence: 99%

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Interneurones in pathways from group II muscle afferents in sacral segments of the feline spinal cord.

Jankowska

Riddell

1994

The Journal of Physiology

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1. Properties of dorsal horn interneurones that process information from group II muscle afferents in the sacral segments of the spinal cord have been investigated in the cat using both intracellular and extracellular recording. 2. The interneurones were excited by group II muscle afferents and cutaneous afferents but not by group I muscle afferents. They were most effectively excited by group II afferents of the posterior biceps, semitendinosus, triceps surae and quadriceps muscle nerves and by cutaneous afferents running in the cutaneous femoris, pudendal and sural nerves. The earliest synaptic actions were evoked monosynaptically and were very tightly locked to the stimuli. 3. EPSPs evoked monosynaptically by group II muscle afferents and cutaneous afferents of the most effective nerves were often cut short by disynaptic IPSPs. As a consequence of this negative feedback the EPSPs gave rise to single or double spike potentials and only a minority of interneurones responded with repetitive discharges. However, the neurones that did respond repetitively did so at a very high frequency of discharges (08-1P2 ms intervals between the first 2-3 spikes). 4. Sacral dorsal horn group II interneurones do not appear to act directly upon motoneurones because: (i) these interneurones are located outside the area within which last order interneurones have previously been found and (ii) the latencies of PSPs evoked in motoneurones by stimulation of the posterior biceps and semitendinosus, cutaneous femoris and pudendal nerves (i.e. the main nerves providing input to sacral interneurones) are compatible with a tri-but not with a disynaptic coupling. Spatial facilitation of EPSPs and IPSPs following synchronous stimulation of group II and cutaneous afferents of these nerves shows, however, that sacral interneurones may induce excitation or inhibition of motoneurones via other interneurones. 5. Comparison of the properties of group II interneurones in the sacral segments with those of previously studied group II interneurones in the midlumbar segments leads to the conclusion that these two populations of neurones are specialized for the processing of information from different muscles and skin areas. In addition, equivalents of only one of the two subpopulations of midlumbar interneurones have been found at the level of the pudendal nucleus: neurones with input from group II but not from group I muscle afferents. Neurones integrating information from group I and II muscle afferents and in direct contact with motoneurones thus seem to be scarce in the sacral segments. 6. On the basis of the patterns of input to sacral group II interneurones it is hypothesized that these interneurones are involved in postural adjustments associated with the defecation and grooming reflexes, as well as some labyrinthine reflexes.We have recently reported that neurones relaying segments, several types of neurones have input from group information from group II muscle afferents are located not II afferents; these include last order interneurones wit...

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Section: Methods Preparationsupporting

confidence: 62%

mentioning

confidence: 91%

Section: Methods Preparationmentioning

confidence: 99%

Section: Methods Preparationmentioning

confidence: 99%

mentioning

confidence: 99%

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Interneurones in pathways from group II muscle afferents in sacral segments of the feline spinal cord.

Jankowska

Riddell

1994

The Journal of Physiology

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Synaptic connections of dorsal horn group II spinal interneurons: Synapses formed with the interneurons and by their axon collaterals

et al. 1997

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Five dorsal horn interneurons with monosynaptic input from group II primary afferent fibres were physiologically characterized and intracellularly labelled with horseradish peroxidase. The cells were prepared for combined light and electron microscopy, and synaptic arrangements formed by axon collaterals of interneurons and synapses formed with their dendrites and somata were examined with the electron microscope. Immunogold reactions for gamma-aminobutyric acid, glycine and glutamate were performed to determine if these synapses were excitatory or inhibitory. Axon collaterals in lamina VI formed synapses with somata and dendrites of other neurons, and collaterals of one cell also formed axoaxonic synapses. It was concluded that one cell from the sample was inhibitory, whereas the remainder were probably excitatory. Dendrites and cell bodies of interneurons were contacted by several types of synaptic bouton. The first type of bouton displayed immunoreactivity for glutamate, the second type contained both gamma-aminobutyric acid and glycine, the third type contained glycine alone, and the fourth type contained gamma-aminobutyric acid alone. Some large glutamatergic boutons were postsynaptic to other boutons. Presynaptic boutons at these axoaxonic synapses always contained gamma-aminobutyric acid but a minority also contained glycine. The results of this study demonstrate the heterogeneity of dorsal horn group II interneurons and provide evidence that they include inhibitory and probably also excitatory neurons. Boutons originating from several chemically different classes of neuron are responsible for postsynaptic inhibition of these interneurons, and the presence of axoaxonic synapses indicates that their excitatory input is also controlled presynaptically.

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Topographical organization of group II afferent input in the rat spinal cord

Riddell

Hadian

1998

J. Comp. Neurol.

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The organization of neurons in the lumbar enlargement of the rat spinal cord processing information conveyed by group II afferents of hind-limb muscle nerves has been investigated by using cord dorsum and intraspinal field potential recording. Group II afferents of different muscle nerves were found to evoke their strongest synaptic actions in specific segments of the lumbar cord. Group II afferents of quadriceps and deep peroneal nerves evoked potentials mainly at the rostral end of the lumbar enlargement (L1-rostral L3), whereas group II afferents of gastrocnemius-soleus and hamstring nerves evoked their main synaptic actions at the caudal end of the lumbar enlargement (L5). In the central lumbar segments (caudal L3-L4), the largest group II potentials were produced by afferents of tibialis posterior and, to a lesser degree, flexor digitorum longus. Field potentials evoked by group II afferents of quadriceps, tibialis posterior, and flexor digitorum longus were largest in the dorsal horn (up to 600 microV), but also occurred in the ventral horn where they were sometimes preceded by group I field potentials. In contrast, field potentials evoked by group II afferents of gastrocnemius-soleus and hamstring nerves were restricted to the dorsal horn. These results indicate that neurons in different segments of the rat lumbar spinal cord process information from group II afferents of different hind-limb muscles. Furthermore, the topographical organization of group II neuronal systems in the rat is similar in several respects to that in the cat and may therefore represent a general organizational feature of the mammalian spinal cord.

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A relay for input from group II muscle afferents in sacral segments of the cat spinal cord.

Cited by 34 publications

References 51 publications

Interneurones in pathways from group II muscle afferents in sacral segments of the feline spinal cord.

Interneurones in pathways from group II muscle afferents in sacral segments of the feline spinal cord.

Synaptic connections of dorsal horn group II spinal interneurons: Synapses formed with the interneurons and by their axon collaterals

Topographical organization of group II afferent input in the rat spinal cord

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