[Morphological characteristics of Lugaro cells of the cerebellar cortex]. / Morfologicheskie osobennosti kletok Lugaro kory mozzhechka.

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.

[Functional organization of the vestibulospinal system in amphibians]. / Funktsional'naia organizatsiia vestibulospinal'noi sistemy u amfibii.

In experiments on the preparation of a frog perfused brain, using recording of intracellular potentials the vestibulospinal neurons were identified on the basis of excitatory postsynaptic potentials evoked by the stimulation of the ipsilateral vestibular nerve and antidromic activation from the stimulation of the cervical and lumbar enlargements of the spinal cord. The average conduction velocity determined for axons of C neurons was 10.67 m/s and for L neurons 15.84 m/s. The ratio of C and L neurons over the vestibular nuclear complex was very stimular to each other: 52% C neurons and 48% L neurons. The majority of both types of neurons were localized in the lateral vestibular nucleus (58.6%), to the lesser extent in the descending vestibular nucleus (30.7%) and very little in the medial vestibular nucleus (10.6%). Fast and slow cells were detected among the vestibulospinal neurons. The fast neurons of L cells did not prevail greatly over the slow ones, whereas the slow neurons of C cells prevailed comparatively largely over the fast neurons. Thus, it became possible to reconstruct spatial distribution of the identified vestibulospinal neurons. The results of spatial distribution of C and L vestibulospinal neurons in the frogs failed to conform to definite somatotopy, which is characteristic for mammalian vestibular nuclei. C and L neurons in the frog's vestibular nuclei as a source of vestibulospinal fibres, are scattered separately or more frequently in groups, so that they establish a "patch-like" somatotopy and do not form a distinctly designed fields as in mammals.

[Effects of pyramidotomy on instrumental reflexes in rats depend on the duration of its execution]. / Effekty piramidotomii na instrumental'nye refleksy u krys v zavisimosti ot vremeni ee provedeniia

The effects of unilateral transection of bulbar pyramids on instrumental conditioned reflexes in rats were shown to be in direct relationship with the time of its execution. In rats with stable conditioned reflexes, pyramidotomy impaired conditioned performance, on the average, for 3.9 days. However, preliminary transection of the pyramid delayed operant conditioning and its stabilization, on the average, by 16.5 day. The findings are discussed in terms of the mechanisms of switching over descending influences of the cortico-spinal and cortico-rubrospinal systems.

[Functional role of the red nucleus in the cerebral cortex-cerebellum-spinal cord communication system]. / Funktsional'naia rol' krasnogo iadra v kommunikatsionnoi sisteme kora mozga-mozzhechok-spinnoi mozg.

Unilateral transection of the rubrospinal tract before lesion of the red nucleus or the ventrolateral thalamic nucleus has been shown to facilitate recovery of operantly conditioned reflexes and compensatory processes in rats. Such strengthening of the recovery plasticity and operantly conditioned was found when transection of the bulbar pyramide performed before ablation of the sensorimotor cortex. These influences are explained by activation of the rubroolivary projection, which is switching of descending cortico-rubrospinal system on the corticospinal system, and on the contrary. The general property of this phenomenon is that preliminary lesion of the peripheral part of the descending spinal projection to acquire a signal forestalling significance for mibilization of compensatory brain capacity in order to recovery the deficit of central link of the system.

[Dynamics of instrumental reflex changes following transection of the corticospinal tract and ablation of the cerebral cortex sensorimotor region in rats]. / Dinamika izmenenii instrumental'nykh refleksov u krys posle pererezki kortikospinal'nogo trakta i udaleniia sensomotornoi oblasti kory mozga.

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.

[The role of ventrolateral thalamic nucleus in switching of the descending influence over to the rat motor activity]. / Rol' ventrolateral'nogo iadra talamusa v perekliuchenii niskhodiashchikh vliianii na dvigatel'nuiu aktivnost' krys.

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.

[Morphologic changes in the rat inferior olive after its neurotoxic destruction with different doses of 2-acetylpyridine]. / Morfologicheskie izmeneniia v nizhnei olive krys pri ee neirotoksicheskom razrushenii razlichnymi dozami 3-atsetilpiridina.

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.

[Compensatory rehabilitation processes and instrumental reflexes in rats after neurotoxic lesions in the inferior olive]. / Kompensatorno-vosstanovitel'nye protsessy i instrumental'nye refleksy u krys posle neirotoksicheskogo razrusheniia nizhnei olivy.

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.

[Functional characteristics of the input-output correlation in the frog vestibular nuclei]. / Funktsional'nye osobennosti korreliatsii vkhoda-vykhoda v vestibuliarnom iadernom komplekse liagushki.

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.

[The histological identification of Lugaro cells in the cat cerebellar cortex]. / Gistologicheskaia identifikatsiia kletok Lugaro v kore mozzhechka koshki.

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.

[The morphofunctional bases of forebrain and cerebellum interaction]. / Morfofunktsional'nye osnovy vzaimodeistviia perednego mozga i mozzhechka.

The article reviews data on structural and functional basis of forebrain and cerebellum interactions. The results of studies of cortical and thalamic structures' neuronal activity under cerebellar influence are considered. Specific and nonspecific cerebello-thalamo-cortical projection systems are analysed. Data on functioning of corticocerebellar loops as well as synaptic transmission in its various links are given. Hypotheses and modern ideas of cerebellocortical interaction' mechanisms are discussed.

[The synaptic inputs of the neurons in the cat parietal associative cortex from the motor cortical area]. / Sinapticheskie vkhody neironov temennoi assotsiativnoi kory mozga koshek iz motornoi korkovoi oblasti.

In anesthetised cats, antidromic activation as well as mono- and polysynaptic EPSPs to cortical motor stimulation, were shown in the parietal cortex's neurons. Functional significance of the cortico-cortical reciprocal connexion between the motor cortex and the parietal associative cortex, is discussed.