My lab studies the birth and incorporation of new neurons in the brains of adult songbirds. New neurons continue to be recruited widely throughout the forebrain of adult birds. In HVC, a region of the forebrain that regulates learned song behavior, there are pronounced seasonal changes in the total number of neurons that are driven by changes in circulating steroid hormone levels and reflect seasonal changes in the rates of neuronal birth and death. Both the division of stem cells in the ventricular zone and the recruitment of differentiated neurons to HVC vary seasonally. We are interested in how hormones act on gene expression and electrical activity of cells to regulate neurogenesis, and the functional significance of this striking form of adult brain plasticity.