Genetic ablation and restoration of the olfactory topographic map

In the olfactory sensory system, neurons expressing a given odorant recepto r project with precision to two of 1800 spatially invariant glomeruli creat ing a topographic map within the olfactory bulb. Olfactory sensory neurons have a half-life of about 90 days and are continually renewing. This poses the problem of how this precise spatial map is maintained throughout the li fe of the organism. We have developed a genetic approach to effect the sync hronous ablation of subpopulations of neurons expressing a given receptor. The axons of newly generated neurons can then be followed as they enter the brain and converge on glomerular targets during adult life. The observatio n that following neuronal cell killing, the spatial map is faithfully resto red, demonstrates that the information necessary for the establishment of t he sensory map persists throughout the life of the organism.