Effect of early sensory experience on the exploratory activity in adult animals.

It was previously found that the exploratory activity of adult Wistar rats with their vibrissae cut in the period from 9 to 20 postnatal days was characterized by lower intragroup variability in comparison with control rats [3]. The present study has shown that the earlier limitation of species-specific afferentation (whisker trimming on postnatal days 2-9) does not induce such changes. We conclude that high plasticity of the brain during the early postnatal period provides better adaptation to the deficit of sensory information.

[EEG in altricial pied flycatcher nestlings during the functional sates related with natural behavior cycle].

Electrical brain activity accompanying various forms of behavior was studied in 11-day-old pied flycatcher nestlings. Wavelet analysis of EEG, recorded from symmetrical areas of caudomedial nidopallium (higher avian auditory center) during rest, passive and active wakefulness and movements showed that the major rhythmical EEG component was confined to low-frequency range in all four states. The significant difference from other states was observed only during movements: spectral power in the range of 1-3 Hz decreased while that in the range of 5-20 Hz--increased.

[Reduction of the number of neurons in substantia nigra (Pars compacta) positively correlates with a reduction of seizure activity in WAG/Rij rats].

In WAG/Rij rats with a genetic predisposition to absence epilepsy, age-related dynamics of seizure activity in the frontal EEG was studied. In parallel, cellular content in substantia nigra was analyzed at the age of 1 and 10 months. In 10-months animals, the number of neurons in substantia nigra showed a profound decrease, whereas the number of glial calls increased.

[Neonatal lesions of catecholaminergic system prevents maturation of cholinergic innervation of the rat neocortex].

The influence ofcatecholaminergic system on functioning of the somatosensory and cholinergic systems in early ontogenesis in rats was studied. The neonatal systemic administration of the neurotoxin 6-hydroxydopamine modifies sensitivity of neurons in the somatosensory cortex to peripheral stimulation (stimulation of the sciatic nerve). It is shown that in animals with lesions, catecholaminergic system reduces the number of the cortical neurons responsive to stimulation of ascending cholinergic pathways.