Limbic neurogenesis/plasticity in the R6/2 mouse model of Huntington's disease.

Huntington's disease is an inherited neurodegenerative condition characterized by movement disorders, and mood and cognitive disturbance. Mammalian neurogenesis persists into adulthood in the subventricular zone and dentate gyrus of the hippocampus. Neurogenesis is abnormal in the dentate gyrus in the R6/2 transgenic mouse model of Huntington's disease. We have now found that the number of immature neurons (doublecortin-positive cells) is markedly reduced in the piriform and insular cortex but not in the temporal germinal layer or caudal subventricular zone of R6/2 mice. Furthermore, numbers of such cells were unaltered in response to seizures in both wild-type and R6/2 mice. These results support the possibility that impaired neurogenesis and/or plasticity could contribute to cognitive and psychiatric impairments in Huntington's disease.