Biomedical subjects

L E Dmitrieva

Publications and source records attributed to L E Dmitrieva.

23 records · Page 2Linked to original sources

PubMedDate not supplied

[Spindle-shaped cortical potentials during rabbit ontogeny].

Studies have been made on total spike activity in the cortex of 3 of 41 days old rabbits. It was shown that in newborn rabbits periodic spindle-like outbursts of high amplitude potentials present typical primary activity of the cortex. This form of activity may be observed both in resting and moving animals. After eye opening, especially beginning from the 16th day, periodic outbursts of high amplitude potentials are observed only during behavioural manifestations of sleep or under nembutal narcosis. During maturation of the cortex, periodic pattern and frequency composition of the outbursts do not undergo any significant changes. Probably, "sleeping spindles" in mature brain are genetically associated with the primary spindle-like activity in the immature cortex, being produced by the same mechanism as the primary spindles in immature cortex.

Age Factors↗

PubMedDate not supplied

[The effect of excess catecholamines on grooming in rats in postnatal ontogeny].

During the first month of postnatal life, studies have been made of the effect of L-DOPA on grooming in rat puppies. It was found that within the first hour after injection of the drug, its inhibitory effect increases in the course of ontogenetic development. In some of the animals, the increase in grooming was observed, whereas in other ones the effect was absent. Inhibition concerns both the number of grooming outbursts and the duration of rhythmic phase. These changes are associated with the decrease of afferent input to the central nervous system and with inhibition of the activity of pacemakers of rhythmic motor excitation.

Aging↗

PubMedDate not supplied

[2 stages in the development of spontaneous motor activity in the early postnatal ontogeny of rats].

In ontogenesis of rats, similar to many other animals, in the development of the spontaneous motor activity two qualitatively different stages are observed. The first one is characterized by periodic, mainly sensor-independent generalized motor excitation which at the second stage is substituted by stereotypic specialized motor programs (locomotion, grooming). Both stages exhibit similar age dynamics: the increase in the activity, its maximum and subsequent inhibition with a shift of the corresponding phases for about two weeks. This dynamics is mainly associated with heterochronous maturation of excitatory and inhibitory systems of regulation of the nervous activity. Change in the stages depends on changes of functional role of motor activity in ontogenesis from mainly morphogenetic one (and promotion of a necessary level of vegetative functions) to directional behavior. Inhibition at the first stage results in deep functional rearrangement in the central nervous system serving as a background for the onset of specialized behavioural activity. The development of the latter is also excessive, the subsequent inhibition being less deep and reversible.

Aging↗

PubMedDate not supplied

[The development of grooming in the ontogeny of rats and mice].

Experiments have been made on rats and mice within the first month of postnatal life. Common age dynamics of grooming reactions for these animals was shown which consists of a sharp intensification of grooming movements at the 3rd week, i.e. at the period of "behavioral arousal", as well as of heterochronous onset of different types of movements which results from successive maturation of the brain structures in which rhythmic centres of these movements are located. Quantitative differences in grooming of rats and mice are presumably due to ecological peculiarities of these animals. Periodic pattern of realization of grooming, as well as the parameters of its rhythmic components suggests that stereotype behavioural reactions are governed by mechanisms of autorhythmic excitation which are typical for the early stages of the development of the nervous system.

Aging↗

PubMedDate not supplied

[The effect of L-DOPA on the motor activity of mouse fetuses].

In the white mice fetus 17-20 days old the motive activity organization is often represented by the single oscillations comprised 63% of the total quantity of motions. 36% of them group into the series, and the generalized activity registered as continuous oscillation complexes is observed only in the single cases. When female is injected subcutaneously with L-DOPA (100 mg/kg) the increase in series oscillations grouping as well as increase in quantity of the continuous activity complexes takes place. It is come to the conclusion that L-DOPA use leads to the revealing for the motive activity features which are characteristics for the older age.

Animals↗