Click here to close
Hello! We notice that you are using Internet Explorer, which is not supported by Xenbase and may cause the site to display incorrectly.
We suggest using a current version of Chrome,
FireFox, or Safari.
Control of frequency during swimming in Xenopus embryos: a study on interneuronal recruitment in a spinal rhythm generator.
Sillar KT
,
Roberts A
.
???displayArticle.abstract???
1. In Xenopus embryos, the frequency of natural and fictive swimming usually drops slowly as swimming continues but can increase following stimulation of the skin or dimming of the illumination. We have investigated whether such increases are associated with an increase in the number of neurones active at higher frequencies. 2. Recordings from ventral presumed motoneurones show that these were reliably active at all swimming frequencies. 3. Recordings from more dorsal presumed interneurones showed that in the majority of these firing probability decreased as a function of swimming frequency. Dye-filled microelectrodes were used to show that some of these neurones had the anatomy of known classes of excitatory and inhibitory premotor interneurones. 4. If skin stimulation is given at appropriate phases of the swimming cycle, it can lead to a transient increase in frequency. Recordings from silent premotor interneurones during such stimulation show that they can be recruited to fire during the post-stimulus frequency increases. 5. It was possible that spike failure in the interneurones could have been due to damage by the recording microelectrodes. We therefore measured the amplitudes and probability of occurrence of rhythmic 'on-cycle' IPSPs which occur in sensory interneurones and 'on-cycle' IPSPs which sometimes occur in motoneurones during fictive swimming. Both decreased in amplitude and could fail as frequency dropped, providing further evidence that the number of inhibitory interneurones firing on each cycle of swimming is a function of frequency. 6. We conclude that premotor rhythm-generating interneurones are not active on all cycles of swimming and that their probability of firing action potentials increases with swimming frequency. This suggests that swimming frequency is determined in part by the number of premotor interneurones which are active.
Andersson,
Peripheral control of the cat's step cycle. II. Entrainment of the central pattern generators for locomotion by sinusoidal hip movements during "fictive locomotion.".
1983, Pubmed
Andersson,
Peripheral control of the cat's step cycle. II. Entrainment of the central pattern generators for locomotion by sinusoidal hip movements during "fictive locomotion.".
1983,
Pubmed
Andersson,
Phasic gain control of the transmission in cutaneous reflex pathways to motoneurones during 'fictive' locomotion.
1978,
Pubmed
Arshavsky YuI,
Control of locomotion in marine mollusc Clione limacina. IV. Role of type 12 interneurons.
1985,
Pubmed
Bernhardt,
Identification of spinal neurons in the embryonic and larval zebrafish.
1990,
Pubmed
Clarke,
Sensory physiology, anatomy and immunohistochemistry of Rohon-Beard neurones in embryos of Xenopus laevis.
1984,
Pubmed
,
Xenbase
Clarke,
Interneurones in the Xenopus embryo spinal cord: sensory excitation and activity during swimming.
1984,
Pubmed
,
Xenbase
Dale,
Inhibitory neurones of a motor pattern generator in Xenopus revealed by antibodies to glycine.
,
Pubmed
,
Xenbase
Dale,
Excitatory synaptic drive for swimming mediated by amino acid receptors in the lamprey.
1986,
Pubmed
Dale,
Dual-component synaptic potentials in the lamprey mediated by excitatory amino acid receptors.
1986,
Pubmed
Dale,
Reciprocal inhibitory interneurones in the Xenopus embryo spinal cord.
1985,
Pubmed
,
Xenbase
Dale,
Excitatory amino acid receptors in Xenopus embryo spinal cord and their role in the activation of swimming.
1984,
Pubmed
,
Xenbase
Grillner,
The adaptation of a reflex response to the ongoing phase of locomotion in fish.
1977,
Pubmed
HUGHES,
The development of the primary sensory system in Xenopus laevis (Daudin).
1957,
Pubmed
,
Xenbase
Kahn,
The neuromuscular basis of swimming movements in embryos of the amphibian Xenopus laevis.
1982,
Pubmed
,
Xenbase
Kahn,
The central nervous origin of the swimming motor pattern in embryos of Xenopus laevis.
1982,
Pubmed
,
Xenbase
Pearson,
Phase-dependent influences of wing stretch receptors on flight rhythm in the locust.
1983,
Pubmed
Roberts,
Intracellular recordings from spinal neurons during 'swimming' in paralysed amphibian embryos.
1982,
Pubmed
,
Xenbase
Roberts,
Descending projections and excitation during fictive swimming in Xenopus embryos: neuroanatomy and lesion experiments.
1986,
Pubmed
,
Xenbase
Roberts,
The neuroanatomy of an amphibian embryo spinal cord.
1982,
Pubmed
,
Xenbase
Roberts,
The anatomy and function of 'free' nerve endings in an amphibian skin sensory system.
1977,
Pubmed
,
Xenbase
Roberts,
Pineal eye and behaviour in Xenopus tadpoles.
1978,
Pubmed
,
Xenbase
Roberts,
The early development of neurons with GABA immunoreactivity in the CNS of Xenopus laevis embryos.
1987,
Pubmed
,
Xenbase
Roberts,
How does a nervous system produce behaviour? A case study in neurobiology.
1990,
Pubmed
,
Xenbase
Roberts,
Characterization and Function of Spinal Excitatory Interneurons with Commissural Projections in Xenopus laevis embryos.
1990,
Pubmed
,
Xenbase
Roberts,
Synaptic potentials in motoneurons during fictive swimming in spinal Xenopus embryos.
1985,
Pubmed
,
Xenbase
SALMOIRAGHI,
Notes on mechanism of rhythmic respiration.
1960,
Pubmed
Shik,
Neurophysiology of locomotor automatism.
1976,
Pubmed
Sillar,
The role of premotor interneurons in phase-dependent modulation of a cutaneous reflex during swimming in Xenopus laevis embryos.
1992,
Pubmed
,
Xenbase
Sillar,
A neuronal mechanism for sensory gating during locomotion in a vertebrate.
1988,
Pubmed
,
Xenbase
Sillar,
Unmyelinated cutaneous afferent neurons activate two types of excitatory amino acid receptor in the spinal cord of Xenopus laevis embryos.
1988,
Pubmed
,
Xenbase
Sillar,
Phase-dependent Modulation of a Cutaneous Sensory Pathway by Glycinergic Inhibition from the Locomotor Rhythm Generator in Xenopus Embryos.
1992,
Pubmed
,
Xenbase
Soffe,
Tonic and phasic synaptic input to spinal cord motoneurons during fictive locomotion in frog embryos.
1982,
Pubmed
,
Xenbase
Soffe,
Active and Passive Membrane Properties of Spinal Cord Neurons that Are Rhythmically Active during Swimming in Xenopus Embryos.
1990,
Pubmed
,
Xenbase
Soffe,
Activity of commissural interneurons in spinal cord of Xenopus embryos.
1984,
Pubmed
,
Xenbase
Soffe,
Roles of Glycinergic Inhibition and N-Methyl-D-Aspartate Receptor Mediated Excitation in the Locomotor Rhythmicity of One Half of the Xenopus Embryo Central Nervous System.
1989,
Pubmed
,
Xenbase
Soffe,
Activity of myotomal motoneurons during fictive swimming in frog embryos.
1982,
Pubmed
,
Xenbase
Soffe,
Ionic and pharmacological properties of reciprocal inhibition in Xenopus embryo motoneurones.
1987,
Pubmed
,
Xenbase
Stehouwer,
Sensory interactions with a central motor program in anuran larvae.
1981,
Pubmed
Wall,
GABAB receptors modulate glycinergic inhibition and spike threshold in Xenopus embryo spinal neurones.
1993,
Pubmed
,
Xenbase
Wolf,
Proprioceptive input patterns elevator activity in the locust flight system.
1988,
Pubmed