Effekte von Enriched Environment auf strukturelle Veränderungen und Verhaltensdefizite nach neonatalen Läsionen des medialen präfrontalen Cortex bei Ratten

In contrast to adult lesions, the ventral medial prefrontal cortex (vmPFC) of rats regenerates after neonatal lesions on postnatal day (PND) 5-12. The present study investigates whether high enriched environment housing conditions (HEE) can attenuate the behavioural deficits which are typically observed after neonatal lesions of the vmPFC. For this purpose rats received bilateral ibotenic acid injections into the vmPFC on PND 7. On PND 21 the rats were dived into a group housed in standard conditions, while the other group was housed in HEE, shamoperated and naïve rats served as controls. While HEE attenuated the vmPFC-lesion induced working memory deficit in the 4-arms baited raialmaze task, and the perseveration behaviour in its reversal, it had no effect on the decreased unconditioned fear in the elevated plus maze. Also HEE seems to have beneficial effects on the performance of neonatal lesioned rats in the food-choice test. Additionally the present study was able to show, that neoatal lesions increase the number of parvalbumine immunoreactive cells in two brain regions interconnected with the vmPFC, namely the basolateral amygdala and the hippocampus.