The Impact of Environmental Enrichment on Neurogenesis in an Animal Model of Autism

Autism, a neurodevelopmental disorder, is assumed to result from early neural tube damage. Individuals with Autism exhibit macroencephaly during childhood. To examine increased neurogenesis as a factor in macroencephaly, the valproic acid (VPA) model of Autism was used to examine how exposure to enrichment affects neurogenesis in the dentate gyrus. To induce the model, pregnant rats received two 100mg/kg VPA injections on days 11, 12, and 13 of gestation. Half the pups in each group were exposed to enrichment from post-natal days 30-60. Neurogenesis was examined by fluorescence microscopy for the proliferation marker bromodeoxyuridine (BrdU) and neuronal specific nuclear marker (NeuN). Counts of double-labeled cells were done from the dentate gyrus, an area known for adult neurogenesis. Results indicate that neurogenesis is not abnormal in the VPA model and enrichment increases the neurogenesis similarly in both VPA and control animals. This research provides a better understanding of brain plasticity in the VPA model of Autism.