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V V Fanardzhian

Publications and source records attributed to V V Fanardzhian.

At least 19 recordsLinked to original sources
PubMed2003

[Morphological characteristics of Lugaro cells of the cerebellar cortex].

Two types of Lugaro cells--fusiform and triangular--were found at different levels of granular layer in the sections of cat cerebellar cortex, stained with silver nitrate using Golgi-Kopsch method. Their processes are oriented horizontally, vertically or obliquely to the folium axis, while their axons never leave the limits of cerebellar cortex, therefore these cells should be considered as interneurons. The processes of Lugaro cells have very large spatial expansion, due to which these cells form numerous axosomatic and axodendritic connections with all the neurons and fibers of the cerebellar cortex. Structural and topographic characteristics of Lugaro cells, as well as the peculiarities of their contacts with the other cells of cerebellar cortex, in combination with the data on their neurotransmitter content, indicate that these cells play the role of inhibitory interneurons.

Animals↗
PubMed2001

[Dynamics of instrumental reflex changes following transection of the corticospinal tract and ablation of the cerebral cortex sensorimotor region in rats].

Unilateral transection of bulbar pyramid performed prior to ablation of the ipsilateral sensomotor cortex was shown to facilitate recovery of operant conditioning and compensatory processes in rats. There was no such corticofugal plasticity in ablation of the sensomotor cortex alone. The phenomenon may be explained by switching of descending influences on the cortico-rubrospinal system through participation of the loop: corticorubral projection--red nucleus--inferior olive--cerebellum--thalamus--cerebral cortex.

Animals↗
PubMed2000

[The role of ventrolateral thalamic nucleus in switching of the descending influence over to the rat motor activity].

Facilitated influence of preliminary transection of the rat rubrospinal tract on motor activity and instrumental reflexes recovering after lesion of the red nucleus was more obvious after a chemical lesion rather than the electrolytic lesion. This seems to be due to remaining cerebello-thalamic fibres after a chemical lesion of the red nucleus. A preliminary destruction of the ventrolateral thalamic nucleus was shown to complicate switching of the motor activity in the rats with transected rubrospinal tract and lesioned red nucleus.

Animals↗
PubMed1999

[Morphologic changes in the rat inferior olive after its neurotoxic destruction with different doses of 2-acetylpyridine].

Neurotoxic effect of 3 acetylpyridine administered in different doses to adult outbred albino rats caused morphological changes in neurons of inferior olive: nucleus translocation towards cell body periphery with central chromatolysis, cytoplasm homogenisation complete dissolution of chromatophilic substance, disappearance of cell contours with glia preservation. The most severe lesion of the nervous tissue was observed in basal olive and dorsal accessory olive in all cases studied. Majority of neurons remained unchanged in medial accessory olive and its subdivisions.

Animals↗
PubMed1998

[Functional characteristics of the input-output correlation in the frog vestibular nuclei].

Field and intracellular potentials were recorded in the vestibular nuclear complex of the frog perfused brain following stimulation of the anterior branch of the ipsilateral vestibular nerve and spinal cord. Mono- and polysynaptic EPSPs with orthodromic APs were recorded from vestibular neurones following vestibular nerve stimulation. Antidromic activation of neurones sending their axons to the labyrinth was also recorded. Antidromic APs of vestibulo-spinal neurones evoked with mean latency of 1.43 and 2.19 ms to stimulation of cervical and lumbar cords, respectively, were revealed.

Action Potentials↗
PubMed1998

[Compensatory rehabilitation processes and instrumental reflexes in rats after neurotoxic lesions in the inferior olive].

Training and recovery of instrumental equilibrium reflexes are impossible after total neurotoxical destruction of the inferior olive in rats. Motor deficits and compensatory rehabilitation processes in rats following 3-acethylpyridine treatment and high transection of the dorso-lateral funiculus of the spinal cord are closely correlated with the degree of the inferior olive destruction. The data obtained revealed an improvement in the motor disturbance and a stabilising of the instrumental reflexes in the rats with subtotal lesion of the inferior olive.

Adaptation, Physiological↗
PubMed1997

[The histological identification of Lugaro cells in the cat cerebellar cortex].

Apart from main classic neuron types there is a small group of neurons known in literature as intermediate Lugaro cells. Two Lugaro cells types are distinguished: fusiform and those with triangular cell body. Fusiform cells vary not only in vertical, horizontal or diagonal position of cell body, but also have certain morphological peculiarities. Axons of some fusiform cells project either to molecular layer or reach Purkinje cells layer or remain at the level of granular layer. Along with it, there are true intermediate cells, described by Lugaro. These cell processes project from layer to layer. Neurons with triangular cell body located at different granular layer levels relate to the second group of Lugaro cells. Due to great extension of their processes Lugaro cells possess projection area ranging from molecular layer to white substance. Lugaro cells are independent neurons, always present in cerebellar cortex.

Aging↗
PubMed1991

[Electrophysiologic properties of red nucleus neurons in the rat brain slices].

Intracellular recordings from the red nucleus (RN) neurons were made in experiments on the rat brain slices. Passive membrane properties (input resistance and membrane time constant) of the RN neurons were evaluated. Phenomena of potential-dependent rebound depolarization and time-dependent inward rectification were revealed by means of passing hyperpolarizing current pulses through the recorded cells. Injections of depolarizing currents caused repetitive firing of neurons with frequencies directly depending on the intensity of injected currents. Repetitive firing was also characterized by a fast frequency adaptation during injections of currents of different intensities. Stimulation of a region of slices presumably corresponding to the decussation of brachium conjunctivum evoked mainly monosynaptic EPSPs with a "fast"-rise time in the RN neurons, which suggests activation of the synaptic input from the cerebellar nucleus interpositus. Stimulation of the same region sometimes evoked EPSP-IPSP mixtures or pure IPSPs in the RN neurons.

Animals↗
PubMed1989

[The collateral branching of the axons of efferent neurons in the cat parietal cortex].

Collateral branching of efferent neurons' axons in the cat parietal associative cortex was studied with intracellular recording of antidromic activity. Specific features of the axon collaterals projecting onto the sensorimotor cortex, pontine nuclei proper and red nucleus, were revealed and described. Information arriving from the parietal cortex simultaneously at the above two motor structures suggests their interrelationship to be actualized through the axon collaterals of efferent neurons. This kind of functional interrelationship of the structures via axon branching of efferent neurons of the parietal cortex provides synchronous arrival of signals at the structures participating in motor integration.

Animals↗
PubMed1988

[Afferent connections of the lateral vestibular nucleus in the cat].

Localization of labelled neurons (sources of projections to the lateral vestibular nucleus) in the brain was studied by means of microiontophoretic injections of horseradish peroxidase. Bilateral projections of the midbrain structures to all parts of the nucleus mentioned (field of Forel, interstitial nucleus of Cajal, oculomotor nerve nucleus and red nucleus) were found. There have been also shown: bilateral projections from more caudally localized structures of the superior, medial and inferior (descending) vestibular nuclei, group "Y" of the vestibular nuclear complex, facial nucleus and hypoglossi, nucleus prepositus nervi hypoglossi and spinal trigeminal nucleus; ipsilateral projections from crus IIa of lobulus ansiformus of the cerebellar hemisphere; contralateral projections from lateral reticular nucleus of medulla oblongata and Deiters' nucleus. Trajectories of the labelled fibre system projecting to Deiters' nucleus are described.

Afferent Pathways↗
PubMed1988

[Characteristics of the neuronal activation of the pontine nuclei proper in the cat in cortico- and cerebellofugal impulse flow].

Antidromic activation of the pontine nuclei neurons evoked by stimulation of brachium pontis, brachium conjunctivum (in rare cases), cerebellar central nuclei, pyramidal tract and sensorimotor cerebral cortex was studied in narcotized cats using the intracellular recording technique. The projection to the cerebellar lateral nucleus was shown to be the most pronounced among pontine nuclear projections. Monosynaptic excitation of the pontine nuclei neurons during stimulation of the pyramidal tract, cerebellar central nuclei and brachium conjunctivum was revealed. Peculiarities and significance of the connections revealed for the functioning of cortico-ponto-cerebellar system are discussed.

Animals↗
PubMed1988

[Neuronal reactions of the central cerebellar nuclei in the waking cat to cortical and peripheral stimuli].

Neuronal responses of the central cerebellar nuclei to electrical stimulation of the cerebral cortex and electrocutaneous stimulation of the limbs were studied in alert cats. An obvious responsiveness of neurons of the fastigial nucleus to the peripheral signals and impulses from the motor cortex was found. The neurons of the n. interpositus responded preferably to peripheral stimuli and signals from the somatosensory cortex. The responses of the medial part of the lateral nucleus to peripheral signals are described, as well as neuronal responses of the lateral nucleus to impulses from the association parietal cortex.

Animals↗
PubMed1987

[Synaptic processes in the rubrospinal neurons evoked by stimulation of the cerebellar nucleus interpositus in the cat].

Activity of red nucleus rubrospinal neurons to electrical stimulation of cerebellar nucleus interpositus was studied in nembutalized cats. Facilitation of cerebello-rubral transmission was shown to take place in the majority of neurons whose focal potentials and EPSPs to paired and frequency stimulation of cerebellar nucleus interpositus were analyzed. The mentioned facilitation was found not to be caused by changes in presynaptic volleys. Discussed modification of the transmission efficiency was supposed to be determined by peculiarities of functioning of cerebellar synapses on red nucleus neurons.

Animals↗