[Structural basis for the regulation of the neuronal sensitivity]. / Strukturnye osnovy reguliatsii chuvstvitel'nosti neironov.

Using light and electron microscopy structural bases for intracellular, extracellular and integrative regulation of synaptic efficiency and neuron sensitivity were established in rat sensomotor cortex. Intracellular regulation is realized basically through modulation of postsynaptic components of the synapse, while extracellular one is provided by synaptic endings of "recurrent" axons on GABA-ergic relay and interneurons. Integrative regulation is realized by means of concentration of similar axonal terminals in restricted cortical area and arrangement of "neuromediatory" pool.

[The neuronal theory and new concepts of the structure of the nervous system]. / Neironnaia teoriia i novye kontseptsii stroeniia nervnoi sistemy.

An analysis of neuron theory modern state was carried out on the base of data from literature and available material. The idea of anatomic, functional and biochemical polarity self-dependence of a neuron and its histochemical polarity have changed significantly. It is said to be confirmed that neuron does not work on its own, its trophics is impossible without glia and one neuron may contain not one but several mediators combined with modulators and regulatory neuropeptides. Postulates on the nervous system module organization seems to be the most well-grounded.

[The identification of synapses in the cerebral cortex]. / Identifikatsiia sinapsov kory polusharii bol'shogo mozga.

The correlation between structure and function of synapses is discussed. Identification of 4 types of synapses has been made based on the authors' own evidence provided for the rat sensomotor cortex with the light and electron microscopy: 1--asymmetrical (excitatory, glutamate- or aspartatergic); 2--symmetrical (inhibitory, GABAergic); 3--symmetrical (disinhibitory, GABAergic); 4--symmetrical or asymmetrical (modulatory, monoaminergic). The ultrastructure of some synaptic categories may be equalized with their function. It makes possible to identify not only excitatory and inhibitory synapses, as considered before, but also disinhibitory and modulatory ones.

[Modular organization of the cerebral cortex]. / Modul'naia organizatsiia kory golovnogo mozga.

Light and electron microscopy original data and other physiological and morphological findings testify that neurons of the cerebral cortex were joined in compact cell ensembles (modules, block). These neuronal modules are self organized in a united morpho-functional system under the repeating impulses which are converged via association callosal and projectional thalamic afferents. A comparative analysis of original and literature data concerning modular organization of the cerebral cortex was performed. A hypothetical model of distinguishing and self assembling of the cortical modules is discussed.

Modules of cortical neurons and their "self-assembly".

The data we have by now accumulated on the cytoarchitectonics of the cerebral cortex, as well as published data, suggest that some of the neurons are structurally combined into compact clusters (ensembles, blocks), and that the majority of them participate in the construction of these clusters by directing the terminal branches of their axons to them. The collaterals of projection, associative, and callosal nerve cells, as well as the axons of interneurons which accomplish local interneuronal closures, can combine individual elements of the ensembles into a unified morphofunctional system. The collaterals of the axons of a block of neurons spread divergently to neurons disposed along the perimeter, while the axons of the latter converge reciprocally to the neurons of the cluster, forming a maximum (focus) of the arborization of the axonal terminals there; this makes it possible actively to isolate modules of nerve cells by accomplishing their self-assembly.

[Cortical neuronal modules and their "self-assembly"]. / Moduli korkovykh neironov i ikh "samosborka".

The light and electron-microscopy original data and other morphological and physiological findings reveal that a population of cortical neurones is gathered in compact cell clusters (blocks, ensembles, modules) and most of neurones participate in maintaining such modules by their axonal ramifications. Some elements of cell clusters may be joined by associative, callosal and projectional thalamic afferents. Authors' new findings are discussed in relation with corresponding literature data. The main attention is given to the self-organization of cortical modules.

[The structural equivalents of the functions in the nervous system]. / Strukturnye ékvivalenty funktsii v nervnoi sisteme.

The article is devoted to the analysis of multiaspect manifestation of morphofunctional interrelation in the nervous system. Significance of morphological data on subcellular, cellular and systemic levels for the creation of physiological conceptions is considered.

[System principles in the organization of neurons carrying out cortical inhibition]. / Sistemnyi printsip organizatsii neironov, osushchestvliaiushchikh korkovoe tormozhenie.

Some new data on neuronal and synaptic organization of sensorimotor cortical area in cat are obtained by a complex of morphological and electrophysiological methods. These data permit considering that direct afferent inhibition is ensured by thalamo-cortical neurons and neurons forming the callosal and association links. The recurrent and lateral inhibition are structurally realized through the ascending recurrent axon collaterals of pyramidal neurons forming links either with short-axon or with long-axon interneurons. Cortico-thalamic (cortico-fugal) inhibition may be performed either via descending cortico-thalamic neurons or via cortico-cortical ipsi- and contralateral neurons. The above mentioned neuronal chains may be considered as structural elements of more complex neuronal sets which ensure the inhibition at the cortical inputs, outputs and intracortically.

[Structural bases of the plasticity of the nervous system]. / Strukturnye osnovy plastichnosti nervnoi sistemy.

The present state of morphological study of variability in the nervous elements under conditions of adaptive change under the influence of afferent effects, age changes during different periods of ontogenesis, under conditions of de- and regeneration of synapses have been considered. A question on correlation between structure and the function of synapses during the change has been analysed. The tasks of subsequent study of this problem have been outlined.

[Neurokinetic hypothesis of synaptic efficiency]. / Neirokineticheskaia gipoteza sinapticheskoi éffektivnosti.

A hypothesis is advanced stating that the dendrite spine is a cilium-like process of the neuron's chemoreceptor membrane provided with sensitive and motor mechanisms. The axo-spinous contacts in the c.n.s. can be controlled by a post-synaptic element. The Ca2+ induces a contraction of the actine molecules contained in the spine base, increases the diameter of the latter and decreases resistance against spreading of the electrotonic potential towards the stem of the dendrite. This mechanism seems to take part in the processes of learning and memory.

[Structural organization of preganglionic sympathetic neurons]. / Strukturnaia organizatsiia preganglionarnykh simpaticheskikh neironov.

Distribution of marked preganglionic neurons over spinal nuclei and segments was studied in cats with the aid of microinjections of the horse-radish peroxidase into the cranial cervical ganglion. The major part of these neurons were revealed in the main part of the intermediolateral nucleus. A somewhat lesser number of the cells were found in the funicular part of the nucleus. In the T1 segment they constituted about 90% of cells containing the peroxidase. Other neurons were localized in the paraependymal and intercalative nuclei. In longitudinal sections of the spinal cord, the preganglionic sympathetic neurons projecting their axons into the cranial cervical ganglion, form a rostro-caudal chain made of small ensembles of cells.

Interneurons of the cat sensorimotor cortex.

In this paper a review is given on the interneurons of the cerebral cortex, their subdivisions and neurophysiology. Special concern is given to short axon (local) interneurons and long-axon (association and callosal) stellate cells. Data obtained from simultaneous recordings of more than one neuron are also presented. However, further research is needed to demonstrate the essential role of the interneurons in information processing.