Perinatal positive and negative influences on the early neurobehavioral reflex and motor development.

Early life events are critical in the development of the central nervous system. Injuries in this period can cause severe damage with permanent disabilities. The early changes following a perinatal lesion have prognostic significance. The nervous system in young age has a potential for plasticity and regeneration, which can prevent the negative effects of neuronal damage, and the most important objective of rehabilitation is to enhance this inner potential of the developing brain. Experimental examination of the environmental factors affecting this regeneration and remodeling process is very important. Endogenous factors, such as neurotrophic factors, which play a role in neurogenesis, migration, and differentiation of neurons, and development of neuronal circuits, are also in the center of interest. Most studies concerning the effect of positive or negative perinatal treatments focus mainly on long-term effects, and most examinations are carried out on adult animals following perinatal injuries. Less data are available on short-term effects and early neurobehavioral changes. In the past several years, we have shown how different (positive or negative) perinatal events affect the early neuronal development. Applying different tests widely used for behavioral testing, we have established a standardized testing method. This includes measuring parameters of somatic growth and facial development, appearance of basic neurological reflexes and also reflex performance, more complex motor coordination tests, and open-field and novelty-seeking tests. In the present chapter, we summarize data on early neurobehavioral development of newborn rats subjected to negative (perinatal asphyxia, hypoxia, excitotoxic injury, stress) and positive (enriched environment, neurotrophic factor treatment) stimuli during early postnatal life.

Environmental enrichment decreases asphyxia-induced neurobehavioral developmental delay in neonatal rats.

Perinatal asphyxia during delivery produces long-term disability and represents a major problem in neonatal and pediatric care. Numerous neuroprotective approaches have been described to decrease the effects of perinatal asphyxia. Enriched environment is a popular strategy to counteract nervous system injuries. The aim of the present study was to investigate whether enriched environment is able to decrease the asphyxia-induced neurobehavioral developmental delay in neonatal rats. Asphyxia was induced in ready-to-deliver mothers by removing the pups by caesarian section after 15 min of asphyxia. Somatic and neurobehavioral development was tested daily and motor coordination weekly. Our results show that rats undergoing perinatal asphyxia had a marked developmental delay and worse performance in motor coordination tests. However, pups kept in enriched environment showed a decrease in the developmental delay observed in control asphyctic pups. Rats growing up in enriched environment did not show decrease in weight gain after the first week and the delay in reflex appearance was not as marked as in control rats. In addition, the development of motor coordination was not as strikingly delayed as in the control group. Short-term neurofunctional outcome are known to correlate with long-term deficits. Our results thus show that enriched environment could be a powerful strategy to decrease the deleterious developmental effects of perinatal asphyxia.