Dual projections of secondary vestibular axons in the medial longitudinal fasciculus to extraocular motor nuclei and the spinal cord of the squirrel monkey

1990 ◽  
Vol 83 (1) ◽  
Author(s):  
L.B. Minor ◽  
R.A. McCrea ◽  
J.M. Goldberg
Keyword(s):  
Spinal Cord ◽  
Squirrel Monkey ◽  
Medial Longitudinal Fasciculus ◽  
Motor Nuclei

Organization of the motor nuclei in the cervical spinal cord of salamanders

1988 ◽  
Vol 278 (2) ◽  
pp. 195-208 ◽  
Author(s):  
David B. Wake ◽  
Kiisa C. Nishikawa ◽  
Ursula Dicke ◽  
Gerhard Roth
Keyword(s):  
Spinal Cord ◽  
Cervical Spinal Cord ◽  
Motor Nuclei

Noradrenergic synapses and effects of noradrenaline on interneurons in the ventral horn of the cat spinal cord

1977 ◽  
Vol 55 (3) ◽  
pp. 399-412 ◽  
Author(s):  
Larry M. Jordan ◽  
David A. McCrea ◽  
John D. Steeves ◽  
John E. Menzies
Keyword(s):  
Spinal Cord ◽  
Close Contact ◽  
Cell Types ◽  
Muscle Afferents ◽  
Ventral Horn ◽  
Lumbar Spinal Cord ◽  
High Threshold ◽  
Depressant Action ◽  
Motor Nuclei ◽  
Lumbar Spinal

Histochemical and electrophysiological procedures were carried out to determine the cell types in the ventral horn which are in close contact with noradrenergic terminals and to identify the types of neurons in the ventral horn which are influenced by noradrenaline (NA). Fluorescence histochemical studies revealed that noradrenaline-containing fibers rarely form intimate contacts with alpha motoneurons, whereas many small interneurons which are closely invested with fluorescent fibers can be found near the motoneurons. The effects of microiontophoretically applied NA on interneurons were examined in the lateral motor areas of the lumbar spinal cord ventral horn. NA had a substantial depressant action on 43% of cells in chloralose-anesthetized and decerebrate cats; it excited 6% of the cells, and was without effect on the rest. The cells which were depressed by NA could be excited by electrical stimulation of high threshold muscle afferents or skin afferents, and they could be influenced from a variety of exteroceptive and proprioceptive inputs. Owing to considerable convergence on the affected interneurons, no distinct population of NA-sensitive interneurons could be identified. Many of the interneurons strongly depressed by NA were found near the motor nuclei. The hypothesis is presented that inhibitory actions of NA on interneurons in the motor nuclei might explain its hyperpolarizing action on motoneurons.

The Location of Spinothalamic Axons within Spinal Cord White Matter in Cat and Squirrel Monkey

1991 ◽  
Vol 8 (2) ◽  
pp. 97-102 ◽  
Author(s):  
Richard T. Stevens ◽  
A. Vania Apkarian ◽  
Charles J. Hodge
Keyword(s):  
Spinal Cord ◽  
White Matter ◽  
Squirrel Monkey

Excitation of lumbar motoneurons by the medial longitudinal fasciculus in the in vitro brain stem spinal cord preparation of the neonatal rat

1993 ◽  
Vol 70 (6) ◽  
pp. 2241-2250 ◽  
Author(s):  
M. K. Floeter ◽  
A. Lev-Tov
Keyword(s):  
Spinal Cord ◽  
Brain Stem ◽  
Short Latency ◽  
Medial Longitudinal Fasciculus ◽  
Paired Pulse ◽  
Long Latency ◽  
The Brain ◽  
Pulse Stimulation ◽  
Stimulation Of

1. The excitation of lumbar motoneurons by reticulospinal axons traveling in the medial longitudinal fasciculus (MLF) was investigated in the newborn rat using intracellular recordings from lumbar motoneurons in an in vitro preparation of the brain stem and spinal cord. The tracer DiI (1,1'-dioctadecyl-3,3,3',3'-tetramethylindocarbocyanine) was introduced into the MLF of 6-day-old littermate rats that had been fixed with paraformaldehyde to evaluate the anatomic extent of this developing pathway. 2. Fibers labeled from the MLF by DiI were present in the cervical ventral and lateral white matter and a smaller number of labeled fibers extended to the lumbar enlargement. Patches of sparse terminal labeling were seen in the lumbar ventral gray. 3. In the in vitro preparation of the brain stem and spinal cord, MLF stimulation excited motoneurons through long-latency pathways in most motoneurons and through both short-(< 40 ms) and long-latency connections in 16 of 40 motoneurons studied. Short- and longer-latency components of the excitatory response were evaluated using mephenesin to reduce activity in polysynaptic pathways. 4. Paired-pulse stimulation of the MLF revealed a modest temporal facilitation of the short-latency excitatory postsynaptic potential (EPSP) at short interstimulus intervals (20–200 ms). Trains of stimulation at longer interstimulus intervals (1–30 s) resulted in a depression of EPSP amplitude. The time course of the synaptic depression was compared with that found in EPSPs resulting from paired-pulse stimulation of the dorsal root and found to be comparable. 5. The short-latency MLF EPSP was reversibly blocked by 6-cyano-7-nitroquinoxaline (CNQX), an antagonist of non-N-methyl-D-aspartate glutamate receptors, with a small CNQX-resistant component. Longer-latency components of the MLF EPSP were also blocked by CNQX, and some late components of the PSP were sensitive to strychnine. MLF activation of multiple polysynaptic pathways in the spinal cord is discussed.

Motor nuclei of peroneal muscles in the cat spinal cord

1988 ◽  
Vol 277 (3) ◽  
pp. 430-440 ◽  
Author(s):  
G. Horcholle-Bossavit ◽  
L. Jami ◽  
D. Thiesson ◽  
D. Zytnicki
Keyword(s):  
Spinal Cord ◽  
Motor Nuclei
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