The evolution of developmental neurobiology. Santiago Ram n y Cajal, Viktor Hamburger, and Rita Levi-Montalcini helped bring order to the study of neuronal development by identifying some of the important questions that still occupy us today. 13.6 Horseradish peroxidase staining. Many of the fundamental discoveries of axon specificity used a technique wherein the plant enzyme horseradish peroxidase was injected into nerves. 13.7 Kallmann syndrome.
Some infertile men have no sense of smell.
The relationship between sense of smell and male fertility was elusive until the gene for Kallmann syndrome was identified as producing a protein that was necessary for the proper migration of both olfactory axons and hormone-secreting nerve cells. The pathways of motor neurons. To innervate the limb musculature, a motor axon extends over hundreds of cells in a complex and changing environment. Recent research has discovered several paths and several barriers that help guide these axons to their appropriate destinations. 13.9 Genetic control of neuroblast migration in C. elegans.