Effects of early postnatal anoxia on adult learning and emotion in rats.

Cognitive functioning, behavioural attention and anxiety were studied in adult male Wistar rats after early postnatal anoxia. Spatial memory performance in the hole board learning task was impaired in anoxic rats when compared with control animals. Attention assessed by the behavioural immobility response to a sudden reduction in background noise was tested in an open field. In anoxic rats this response was reduced compared to controls, which was further reflected in a higher ambulation score in anoxic animals. The emotional state in adult rats after postnatal anoxia was not affected as was demonstrated in the elevated plus-maze and in the shock probe/defensive burying task. The results indicate that adult cognitive deficits after neonatal anoxia are not related to changes in emotional behaviour. Disruption of behavioural attention or the capacity of concentration to task performance may, however, contribute to the observed cognitive impairment.