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PubMed1974

Effects of postnatal influences on conditioning and some functional and structural brain parameters in rats.

Early postnatal influences were studied in rats in three different ways: (i) different litter size, (ii) feeding with restricted amount of protein, (iii) different level of afferent stimulation. A complex evaluation of spontaneous activity, conditioning, electrophysiological and biochemical analyses was used in these experiments. Medium sized litters showed the greater electrophysiological reactivity (cortical evoked potentials) and the most stable performance in different kinds of conditioning (avoidance) experiments. Animals reared on a low protein diet were subnormal in electrophysiological indices, and had a lower level of biochemical activity for materials Involved in neural excitability, electrogenesis, and cellular and subcellular energetic metabolism (phospholipids, proteins, DNA, RNA). In all respects (behavioral, electrophysiological and biochemical tests) animals with partial sensory deprivation in the postnatal period had the lowest indices. The "stimulated" animals on the other hand were superior to both other groups in the tests used for the analysis of higher nervous activity, but electrophysiological and biochemical analyses did not show clear differences between the "stimulated" and control animals. Optimal development of brain functions requires adequate conditions in the early postnatal period. However, the "adequacy" of them conditions has dill to be determined more precisely.

Animals↗
PubMedDate not supplied

[Dynamics of the statistical indices of evoked potentials in modally specific brain structures during the formation of defensive reflexes].

Interdependence of integrative processes in the relays of the analyzers of signal stimuli (auditory and visual) was estimated by EP parameters (latency, amplitude, and duration) of the first positive and negative components. It has been shown that the significance of the coefficients of correlation between EP parameters in the studied structures is determined by the stage of the behaviour formation; it also depends on the EP component chosen for the analysis. Significant correlation coefficients are timed to the active period in the formation of defensive conditioned reaction. In this period significant correlation coefficients for the parameters of the first positive EP component are established in various fields of cortical projection zones and between the parameters of the negative component in all relays of the analyzer. The data are treated from the viewpoint of adaptation of the analyser activity to the organism's needs at each stage in the formation adaptive behaviour and of the role of motivational influences in the organization of intraanalyzer integrations.

Adaptation, Physiological↗