Light microscopic observations on the relationships between 5-hydroxytryptamine-immunoreactive axons and dorsal spinocerebellar tract cells in Clarke's column in the cat

1999 ◽  
Vol 130 (3) ◽  
pp. 320-327 ◽  
Author(s):  
J. C. Pearson ◽  
M. J. Sedivec ◽  
D. E. Dewey ◽  
R. E. W. Fyffe
Keyword(s):  
Spinocerebellar Tract ◽  
Clarke's Column ◽  
Immunoreactive Axons

Dorsal Spinocerebellar Tract Neurons Are Not Subjected to Postsynaptic Inhibition During Carbachol-Induced Motor Inhibition

1997 ◽  
Vol 78 (1) ◽  
pp. 137-144 ◽  
Author(s):  
Ming-Chu Xi ◽  
Jack Yamuy ◽  
Rong-Huan Liu ◽  
Francisco R. Morales ◽  
Michael H. Chase
Keyword(s):  
Spinal Cord ◽  
Membrane Potential ◽  
Synaptic Activity ◽  
Motor Inhibition ◽  
Postsynaptic Inhibition ◽  
Postsynaptic Potentials ◽  
Group I ◽  
The Mean ◽  
Spinocerebellar Tract ◽  
Clarke's Column

Xi, Ming-Chu, Jack Yamuy, Rong-Huan Liu, Francisco R. Morales, and Michael H. Chase. Dorsal spinocerebellar tract neurons are not subjected to postsynaptic inhibition during carbachol-induced motor inhibition. J. Neurophysiol. 78: 137–144, 1997. Dorsal spinocerebellar tract (DSCT) neurons in Clarke's column in the lumbar spinal cord of cats anesthetized with α-chloralose were recorded intracellularly. The membrane potential activity and electrophysiological properties of these neurons were examined before and during the state of active-sleep-like motor inhibition induced by the injection of carbachol into the nucleus pontis oralis. The synaptic activity of DSCT neurons during carbachol-induced motor inhibition did not change compared with that during control conditions. In particular, there was an absence of inhibitory postsynaptic potentials (IPSPs) in high-gain recordings from DSCT neurons and the resting membrane potential of DSCT neurons was not significantly hyperpolarized during carbachol-induced motor inhibition. The mean amplitude of both monosynaptic excitatory postsynaptic potentials and disynaptic IPSPs evoked in DSCT neurons following stimulation of group I muscle afferents after the injection of carbachol was similar to that evoked before the injection of carbachol. There were no significant changes in the mean input resistance and membrane time constant of DSCT neurons during carbachol-induced motor inhibition. We conclude that, in contrast to lumbar motoneurons, DSCT neurons in Clarke's column are not postsynaptically inhibited during carbachol-induced motor inhibition. Therefore the population of spinal cord Ib interneurons that inhibit both DSCT neurons and lumbar motoneurons is not likely to be the interneurons that are responsible for the postsynaptic inhibition of motoneurons that occurs during carbachol-induced motor inhibition. The present findings also indicate that transmission through the DSCT is not modulated by postsynaptic inhibition at the level of DSCT neurons during carbachol-induced motor inhibition.

scholarly journals Origin of a Non-Clarke’s Column Division of the Dorsal Spinocerebellar Tract and the Role of Caudal Proprioceptive Neurons in Motor Function

Cell Reports ◽  
2015 ◽  
Vol 13 (6) ◽  
pp. 1258-1271 ◽  
Author(s):  
Rachel Yuengert ◽  
Kei Hori ◽  
Erin E. Kibodeaux ◽  
Jacob X. McClellan ◽  
Justin E. Morales ◽  
...  
Keyword(s):  
Motor Function ◽  
Spinocerebellar Tract ◽  
Clarke's Column

scholarly journals Do premotor interneurons act in parallel on spinal motoneurons and on dorsal horn spinocerebellar and spinocervical tract neurons in the cat?

2011 ◽  
Vol 105 (4) ◽  
pp. 1581-1593 ◽  
Author(s):  
Piotr Krutki ◽  
Sabina Jelen ◽  
Elzbieta Jankowska
Keyword(s):  
Dorsal Horn ◽  
Muscle Afferents ◽  
Feedback Information ◽  
Postsynaptic Potentials ◽  
Reflex Pathways ◽  
Different Populations ◽  
Spinocerebellar Tract ◽  
Motor Nuclei ◽  
Clarke's Column ◽  
Electrical Stimuli

It has previously been established that ventral spinocerebellar tract (VSCT) neurons and dorsal spinocerebellar tract neurons located in Clarke's column (CC DSCT neurons) forward information on actions of premotor interneurons in reflex pathways from muscle afferents on α-motoneurons. Whether DSCT neurons located in the dorsal horn (dh DSCT neurons) and spinocervical tract (SCT) neurons are involved in forwarding similar feedback information has not yet been investigated. The aim of the present study was therefore to examine the input from premotor interneurons to these neurons. Electrical stimuli were applied within major hindlimb motor nuclei to activate axon-collaterals of interneurons projecting to these nuclei, and intracellular records were obtained from dh DSCT and SCT neurons. Direct actions of the stimulated interneurons were differentiated from indirect actions by latencies of postsynaptic potentials evoked by intraspinal stimuli and by the absence or presence of temporal facilitation. Direct actions of premotor interneurons were found in a smaller proportion of dh DSCT than of CC DSCT neurons. However, they were evoked by both excitatory and inhibitory interneurons, whereas only inhibitory premotor interneurons were previously found to affect CC DSCT neurons [as indicated by monosynaptic excitatory postsynaptic potentials (EPSPs) and inhibitory postsynaptic potentials (IPSPs) in dh DSCT and only IPSPs in CC DSCT neurons]. No effects of premotor interneurons were found in SCT neurons, since monosynaptic EPSPs or IPSPs were only evoked in them by stimuli applied outside motor nuclei. The study thus reveals a considerable differentiation of feedback information provided by different populations of ascending tract neurons.

Location and morphology of dorsal spinocerebellar tract neurons that receive monosynaptic afferent input from ankle extensor muscles in cat hindlimb

1990 ◽  
Vol 63 (2) ◽  
pp. 286-293 ◽  
Author(s):  
B. Walmsley ◽  
M. J. Nicol
Keyword(s):  
Afferent Input ◽  
Cross Sectional ◽  
Dendritic Trees ◽  
Root Entry Zone ◽  
Group I ◽  
Extensor Muscles ◽  
Dorsal Columns ◽  
Previous Proposal ◽  
Spinocerebellar Tract ◽  
Clarke's Column

1. The present experiments were carried out to investigate the morphology and somatotopic location of dorsal spinocerebellar tract (DSCT) neurons that receive monosynaptic group 1 afferent input from hindlimb ankle extensor muscles in the cat. 2. Intracellular recordings were obtained from DSCT neurons throughout the rostrocaudal extent of the L3 dorsal root entry zone of the spinal cord. DSCT neurons, physiologically identified as receiving monosynaptic group I input from the ankle extensor muscles, were injected with horseradish peroxidase (HRP) and subsequently reconstructed under the light microscope. 3. In contrast to previous HRP studies of DSCT neurons, these cells were found to have extremely extensive and complex dendritic trees, that often extend beyond the region of Clarke's column. Dendrites were found to extend into the white matter of the dorsal columns, and/or into the spinal gray matter in a ventrolateral direction. The large dendritic spread of DSCT neurons was found to occupy up to 60% or more of the cross-sectional area of Clarke's column. 4. DSCT neurons receiving monosynaptic group I input from the single functional group of ankle extensor muscles were not found to be confined within a specific transverse region of Clarke's column, in contrast to a previous proposal. Instead, these cells could be found throughout Clarke's column. 5. The present results demonstrate that DSCT neurons, physiologically identified as receiving group I muscle afferent input, exhibit dendritic trees that are considerably more extensive and morphologically complex than indicated by previous studies. In addition, the present results do not support a previous proposal of a strict somatotopic arrangement for DSCT neurons and their dendritic envelopes within Clarke's column in the transverse plane.

Sign in / Sign up

Export Citation Format

Share Document