The effect of different anamnesis during ontogeny on higher nervous activity in rats.

The consequences of malnutrition, experimental experience and sensory deprivation during early postnatal life were investigated in adult rats. The higher nervous activity of experimental animals was evaluated by means of a battery of tests (exploratory activity, avoidance reaction, preference of a small chamber and a water maze). Rats were divided into 5 groups, i. e. control, trained (with previous experimental experience), light deprived, malnourished naive (12-14 animals in the litter) and malnourished trained. From experimental data obtained it may be concluded that the level of nutrition as well as sensory deprivation or additional stimulation during development are important factors the influence of which persists and modifies the somatic development and the higher nervous activity in adult animals. Light deprived and malnourished rats showed retarded somatic development and worse parameters of higher nervous activity. The difference between groups could be altered by augmented stimulation. Previous experimental experience and intensive handling seems to be an important factor which influences the higher nervous activity of experimental animals.

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.