Cellular interactions in the development of the olfactory system: An ablation and homotypic transplantation analysis

lit the current study, we addressed two questions: First, Is the olfactory placode necessary for the development of the olfactory bulb and the entire telencephalon? Second, does the olfactory placode contribute cells to the o lfactory bulb? We addressed these questions by unilaterally ablating the ol factory placode in chick embryos before an olfactory nerve was produced and , in a second series of experiments, by replacing the ablated chick olfacto ry placode with a quail olfactory placode. Our results indicate that the ol factory placode is critical for olfactory bulb development, but is not nece ssary for the development of the rest of the telencephalon. Further, our re sults support the hypothesis that LHRH neurons and olfactory nerve glia ori ginate in the olfactory placode, but do not support an olfactory placodal o rigin for other cell types within the olfactory bulb. (C) 2001 John Wiley & Sons, Inc.