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G L Fel'dman

Publications and source records attributed to G L Fel'dman.

12 recordsLinked to original sources
PubMed1983

[Ribosome number of the satellite glia and neuroglial relationship in the cerebral cortex of the cat in the wakefulness-sleep cycle].

The ultrastructural analysis of satellite glia cells and adjacent large pyramidal neurons of parietal cortex of the cat showed regular changes in the amount of ribosomes in various phases of the wakefulness-sleep cycle. These changes have a reciprocal character in glia and neurons. During the slow wave phase of sleep (SWS) in comparison with wakefulness (W) the amount of glial ribosomes in a unit of electronogram area increased, while in neurons it decreased. In the paradoxal phase of sleep (PS), the number of ribosomes in glia, compared with SWS, decreased, but in neurons at the same time it increased. Variations in the amount of ribosomes of glial cell cytoplasm are most prominent in the zone of contact with the neuron. The obtained data suggest a link in protein metabolism of neurons and glia, and the changes in neuroglial relationship during sleep development.

Animals↗
PubMed1981

[Responses of parietal cortex neurons during the process of sleep onset in the cat].

Neuronal responses in the cat parietal cortex to stimulation of thalamic radiation during transition from wakefulness to slow-wave sleep revealed a complex dynamics: the cyclic nature of responses at early sleep stages became more obvious with the enhancement of activity (during the "sleep spindles"); in subsequent stages inhibitory components prevailed. Three types of neurons with different response dynamics were revealed, the differences being due to their functional and hierarchical characteristics.

Afferent Pathways↗
PubMed1980

[Protein synthesis in the large cortical pyramidal neurons during the paradoxical phase of sleep].

A study was made of the quantity of ribosomes and autographs in the large pyramids of the cat brain pariental region during the wake (WS) and paradoxal sleep (PS) by methods of electron microscopy and autoradiography. Unlike the slow wave phase of sleep, a high level of protein synthesis was established both in PS and in WS. PS in contrast to WS, is characterized by a reliable increase in the number of membrane-bound ribosomes and decrease in the quantity of polysomes and intracellular distribution of autographs.

Animals↗
PubMed1979

[Topography and the protein synthesis level in the large pyramidal neurons during sleep and wakefulness].

In the large pyramidal neurons of the pariental cortex of cat during the slow-waved phase of sleep in comparison to the state of awake, an uneven decrease of the level of 3H-leucine inclusion was established in different functionally specialized zones of the cell. Using electron microscopy, a decrease in the number of polysomes and membrane-attached ribosomes was shown in the perinuclear zone of large pyramids in slow-waved phase of sleep. The results obtained suggest a decrease in the intensity of protein synthesis in comparison to the state of awake.

Animals↗
PubMed1975

[Evoked activity of cat association cortex neurons in different sleep stages].

Evoked activity of neurons in the parietal associative cortex in response to adequate and electric stimulations of the thalamic radiation fibers was studied during different phases of sleep. The number of responding neurons decreased during slow--wave and, particularly, during paradoxical sleep. With transition from phase to phase, responsiveness changed mainly in polysensory neurons which gave variable responses with long latencies. Mechanisms of change of responsiveness during the two phases appear to be different. Reliable increase of the inhibitory pause in responses during slow-wave sleep and its decrease during paradoxical sleep may indicate a strengthening of mechanisms of reciprocal inhibition during the first phase, and their weakening during the second phase.

Animals↗
PubMedDate not supplied

[Interaction of systems generating spindles and delta waves as a possible mechanism for the development of slow-wave sleep].

Certain correlations between spindling and delta-activity during slow-wave sleep (SWS) development have been studied in experiments on man and animals. Interaction between systems of delta-activity and spindling generation is discussed as a possible mechanism underlying development of SWS. Amplitude-modulated stimulation of non-specific thalamic structures has been shown to influence this interaction and development of sleep processes.

Animals↗
PubMedDate not supplied

[Spatio-temporal organization of ECoG spindles during sleep onset].

Spatio-temporal organization of spindle activity in the cerebral cortex during deepening of slow-wave sleep (SWS) was studied in experiments on cats and rabbits. Patterns of both "sleep" and recruiting reaction spindles were analyzed. In the process of sleep development spindle activity was transformed from local to a diffuse one, organized in a sort of packages. The rate of synchroneity in spindle packages depended on the sleep depth. At the deepest SWS stages a sharp desynchronization of spindles in the packages was observed and then--complete disappearance of spindle activity. Interaction of thalamic spindle pacemakers seems to play an important role in the mechanism of SWS development; changes in it result in reorganization of spindle activity on the cortical surface. A considerable part in this interaction is reserved to the processes of emergence and spread of delta-activity.

Animals↗
PubMedDate not supplied

[Thalamo non-specific system at different stages of sleep and wakefulness].

Cortical respones to low-frequency (6 to 8 per sec) rhythmic stimulation of the Centrum medianum thalami have been studied in chronic experiments on cats. Three types of recruiting reactions have been readily obtained: 1) with periodic spindling of response amplitudes, the sustained oscillatory type; 2) with spindling only at the beginning of stimulation, the decaying oscillatory type, and 3) with equal amplitudes throughout the stimulation, the aperiodic type. Distinct changes in the type of reactions have been shown--from the aperiodic to the sustained oscillatory type during transition of active awake state to slow-wave sleep, and from the sustained oscillatory type to the aperiodic type during transition of slow-wave sleep to the paradoxical sleep, which is due to changes in the weights of feedbacks in the thalamo-cortical nonspecific system.

Animals↗