O. A. Karamyan

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The structure of connections between lumbar motoneurons was investigated in preparations of spinal cord isolated from young rats. This involved applying horseradish peroxidase to the ventral root and intracellular injection of the same enzyme into motoneurons. The possibility of dendro-dendritic, dendro-somatic, and somato-somatic contacts between(More)
Intracellular investigations into interaction between lumbar motoneurons were made during ventral root stimulation in spinal cord isolated from 9 to 14-day-old rats and horseradish peroxidase injection. It was found that electronic interaction is brought about by contacts between a moderate number of adjacent motoneurons and does not lead to generation of(More)
A comparative analysis of neurochemical organization of pretectal nuclei was performed on the basis of results of our studies on immunoreactivity to monoamines (tyrosine hydroxylase—TH and serotonin—5-HT), neuropeptides (substance P—SP, met-enkephalin—mEnk, and neuropeptide Y, NPY), and gamma-aminobutyric acid (GABA) in pretectum of two turtle species, as(More)
Structuro-functional correlations in the organization of connections between primary afferent fibers and motoneurons were investigated in the lumbar segments of spinal cord from 1–2-week-old rats. A single afferent fiber collateral was found to make contact with an individual motoneuron. There could be up to 10 boutons making contact. The n parameter of the(More)
Intracellular recording and computer averaging used in experiments on monkeys (Macaca rhesus) showed that fast-conducting reticulo- and vestibulospinal fibers form monosynaptic excitatory connections with lumbar α-motoneurons. Monosynaptic bulbo spinal influences remain intact after division of the pyramids or destruction of the motor cortex. The mean(More)
1. All investigated mesencephalic structures have definite synaptic influences on spinal α-motoneurons. The red nucleus facilitates flexor and inhibits extensor motoneurons. The substantia nigra acts in the same way as the red nucleus on motoneurons, but with less marked reciprocity. The reticular formation and nucleus of Cajal excite all of the flexor and(More)
It was established in experiments on rhesus monkeys by intracellular recording and computer averaging that fast-conducting reticulo- and vestibulospinal fibers form monosynaptic excitatory links with lumbar alpha-motor neurons. The monosynaptic bulbospinal effects are retained after sectioning of the pyramids or after chronic destruction of the motor(More)
Postsynaptic potentials evoked by stimulation of the motor cortex or pyramids before and after acute pyramidotomy were investigated in the lumbar motoneurons of monkeys. In response to activation of fibers of the pyramidal tract monosynaptic EPSPs predominated in motoneurons innervating the distal muscles of the hind limbs. Monosynaptic EPSPs in the(More)
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