[Ultrastructural changes in the cerebral cortex of an 100 1/2-year-old man]. / Ul'tramikroskopicheskie izmeneniia kory bol'shogo mozga cheloveka 100 let 6 mesiatsev.

Age changes in fields 39 and 40 (after Broadman) have been studied in a 100 years and 6 months old man died from peritonitis resulted from the surgical intervention, performed in connection with strangulation of the hernia. In the medical history there were no ++neuro-physical signs. The material was taken in 1 h 15 min after clinical death had been stated. The results obtained have been compared with those studied in the brain of persons, who had not yet reached the age of 100 years and had not any signs of ++neuro-physical disturbances and died after urgent surgical interventions in the abdominal cavity. In this group of persons the material for investigation was taken in 15-30 min after clinical death had been stated. The technique for treatment the material, its preparation for electron-microscopical examination is identical. Immersion fixation has been applied. The material obtained from an old animal fixed by means of vital perfusion of 2.5% glutaraldehyde solution is also used. In the person of 100 years and 6 months old the changes do not practically differ from those obtained from persons of younger age, however, the time from the statement of clinical death up to obtaining the material essentially influences preservation of the synaptic apparatus components.

[Ultrastructure of epileptic foci in temporal epilepsy]. / Ob ul'trastrukture épilepticheskikh ochagov pri visochnoi épilepsii.

An electron microscopy study was conducted on the material of biopsies from the removed epileptic foci localized in the hippocamp and fields 21 and 38 of the temporal cortex of 11 patients with temporal epilepsy. There was the constant presence of so-called dark and altered light neurocytes whose cytoplasm had experienced considerable changes and was saturated with various inclusions. The axons and dendrites of the cells underwent peculiar degeneration. The authors revealed multiple agglutination of synaptic vesicles in the preterminals and synaptic buds, and also dark degeneration of the axonal endings in the absence of Waller's degeneration of axons. Marked changes in the walls of the capillaries were also found.

[Special forms of ultrastructural changes in dendrites and axons in the human and cat brain]. / Osobye formy ul'trastrukturnykh izmenenii dendritov i aksonov v mozge cheloveka i koshki.

The investigation has been performed in the human brain of persons at the age of 75-87 years, in the auditory cortex of old cats and in bioplates obtained from epileptic foci of the hippocamp and the temporal cortex of 11 patients suffering from temporal epilepsy (at the age of 12-29 years). Distal parts of the dendrites contain a large amount of myelin-like membranous and electron opaque inclusions. In most cases these dendrites have no axodendritic contacts. In large trunks of the dendrites there are noted a comparatively large number of neurotubules with definitely seen contours against the background of small conglomerates of loose fine fibrillar material. Myelin axons contain a large amount of sharply contoured neurotubules which fill axoplasm. Similar dendrites and axons are revealed in the cerebral cortex both at age changes and in tissue of the epilepsy foci. These changes are supposed to result from the effect of the same factor.

The morphological basis of age-induced memory changes.

The results are presented of a layer-by-layer electron microscopic study of the cortex (40th area) in persons aged 78, 79, and 83 years whose anamneses did not include any neuropsychic disorders and who had died during surgical intervention These findings are examined in the light of current hypotheses about the morphological substrate of the mechanisms of memory. Cortical changes are uncovered which, according to these hypotheses, lie at the basis of the memory mechanisms. These include changes of the cytoplasm, neurocytes, dendrites, spines, axons, and their terminals. The same types of changes are found in the auditory cortex of old cats used for the control of the degree of preservation of elements of the human cortex.

[Age-related changes in interneuronal synapses in human cerebral cortex]. / Vozrastnye izmeneiia mezhneironnykh sviazei kory bol'shogo mozga cheloveka.

In 5 persons that did not suffer from any psychical or neurological illnesses, at the age of 75-83 years, ultrastructure of dendrites, axons and axonal terminals was studied in the 40th field of the cerebral cortex, layer after layer. Various forms of changes in the dendrites were revealed demonstrating certain degenerative alterations in them and their loss of synaptic contacts with the axonal terminals. Two types of the axonal changes were followed. One of them, the most spread, has features of functional alterations (a tight arrangement of a great number of coarse neurotubules, while the axoplasm is remained). The state of such fibers is considered by the authors as a reversible one. Changes of the other type of axons (they are deprived of normal organells of axoplasm) are considered by the authors as irreversible. Degeneration of the axonal terminals, noted in all cortical layers, is realized mainly according to the "dark" type and seldom--according to the "light" one. In most cases these contacts are performed by unchanged dendrites. A gradual degeneration and death of neurocytes should be considered as a main course of the disturbances in the interneuronal connections of the cortex.

[Morphological bases for age changes in memory]. / Morfologicheskie osnovaniia vozrastnykh izmenenii pamiati.

The electrone microscopy of cerebral cortex (the 40th Brodmann's area) in 78, 79 and 83-year-old humans with no nervous or psychic disturbances and deceased during surgical intervention revealed significant changes of neuronal cytoplasm, dendrites, spines, axons and axonal synaptic terminals. Ultrastructural investigation of different acoustic areas of old cats cortex revealed the same changes and served as the control of harmlessness of the studies in humans. According to modern hypothesis on the memory mechanisms and their morphological substrate, the changes discovered in human cerebral cortex may serve as a possible cause of the age-induced memory changes.

[Age-related changes in the dendrites in the cat cerebral cortex (an electron microscopic study)]. / Vozrastnye izmeneniia dendritov v kore bol'shogo mozga koshki (élektronno-mikroskopicheskoe issledovanie).

Various zones of the acoustic cortex (A1, A3, A4, Ep after Voolsey) have been serially studied in two cats 12-14 years of age at electron microscopic level. Various forms of age changes have been revealed in their dendrites. The most often occurring form of the changes is the dendrites with lipofuscin granules in them. The dendrites with neuroplasm filled with numerous, sometimes aggregating electron opaque formations of various size and contour make the second form. Appearance of separate electron opaque round myelin-like bodies scattered in the dendritic neuroplasm precede the appearance of the third form. There is a various degree of disturbances in the interneuronal contacts. They depend on age alterations in the dendrites which are the most widespread postsynaptic components in the cerebral cortex. The importance to perform age selection of animals for an experimental morphological interneuronal connection investigations is stressed.

[Changes in the cerebral cortex in temporal lobe epilepsy]. / Izmeneniia v kore golovnogo mozga pri visochnoi épilepsii.

Biopsy specimens of the temporal cortex were taken from three patients suffering from temporal epilepsy of different origin. As a result of examining the specimens under optic and electron microscopes and subsequent morphometric processing of the data a picture of layer-by-layer changes in the cortex (field 21/38) was obtained. These changes consisted in appearance of the so-called dark cells, degenerating synaptic buds and myelin fibres, and increase of the percentage of astrocytes and proliferation of their processes. The data obtained suggest that in this disease there occurs a gradual destruction of neurocytes which leads to disturbances of the interneuronal relations.

[Connections between cat brain visual cortex fields 18 and 19 passing through the white matter]. / Sviazi mezhdu poliami 18 i 19 zritel'noi kory mozga koshki, prokhodiashchie cherez beloe veshchestvo.

Distribution of degenerating synaptic boutons in fields 18 and 19 of the cat cerebral visual cortex was studied in every layer electron microscopically after the white substance was dissected under one of these fields. It was demonstrated that the V-shaped system under investigation consisting of associative fibres connects four superficial cortical layers (in layers V and VI of fields 18 and 19 no altered synapses were detected), while the intracortical system of conductors unites all six layers of the fields mentioned. The number of synapses, degenerating ones including, terminating on large and small dendrites and on thorns of every layer of fields 18 and 19 were counted. Possible functional differences between intracortical and V-shaped systems of the associative fibres in fields 18 and 19 of the cat visual cortex is discussed.

[Effect of single gravitational overloading on various parts of the brain (experimental electron and light microscopic study)]. / Vliianie odnokratnykh gravitatsionnykh peregruzok na nekotorye otdely golovnogo mozga.

After application of single gravitational overloadings on the cat brain, perivascular edema, peripheral chromatolysis and cytoplasmic edema in neurons, dendrites and astrocytes have been observed. Some shifts in ultrafine composition of presynaptic buds and vascular walls have been described. Structures of myelin and amyelin fibers are preserved. Ultrastructural reconstructions are expressed differently in different brain structures in connection with their functional differentiation. The reconstructions revealed are of reversible character.

[Intracortical connections between fields 18 and 19 of the visual cortex of cat's brain]. / Vnutrikorkovye sviazi mezhdu poliami 18 i 19 zritel'noi kory mozga koshki.

To study electron microscopically intracortical connections between areas 18 and 19 in the visual cortex of the cat brain, the distribution of synaptic terminals in every lamina of these areas was investigated after dissection of their border as deep as the grey matter. Mainly axo-dendritic synapses in large, small dendrites and in spines degenerated according to "light" and "dark" types were subjected to degeneration. All the laminae of the cortex were stated to participate in the formation of overlapping intracortical connections of areas 18 and 19. The greatest nember of altered synaptic buds, however, were detected in the middle layers, that correlated the data of the light optic method (A. S. Iontov, 1961, 1962). To obtain more objective data on the number of intracortical fibrils connecting these areas, normal and altered synapses up to 100 units were counted in every layer. Uneven localization of intracortical connections in every layer and their different functional importance were demonstrated.