Organization and Function of the Extra-Bulbar Olfactory Pathway

点击翻译按钮获取中文摘要

Evolutionary changes in the nervous system offer a tremendousopportunity to understand the relationship between the nervous system andbehavior. When new brain structures are created, what does this do to anorganism's behavior? How do these new structures interact with otherportions of the nervous system? We are usingthe vertebrate olfactory system (the system responsible for the sense ofsmell) as a model for examining evolutionary changes in the nervous system.To this end, we are exploring the organization of the olfactory system ina variety of vertebrate animals. Recently, scientists have learned that receptor cells in the noseof some fishes and amphibians are connected to the a region in the base ofthe forebrain, instead of to the olfactory bulbs, as is usual for thesecells. The structure of this newly-discovered subsystem, the "extra-bulbarpathway," is poorly understood, and its function has not been investigated.In the proposed experiments, the location of the receptor cells of theextra-bulbar pathway within the nose will be examined in adult axolotls(Ambystoma mexicanum), a salamander species that lives in water throughoutits life. Single-cell electrophysiological recording methods will be usedto study the odorant response properties of the receptor cells of theextra-bulbar pathway in axolotls. These experiments will allow us toexamine the function of the extra-bulbar pathway, andto test an interesting hypothesis that suggests that the extra-bulbarpathway functions in detection of pheromones. Pheromones are chemicalsproduced by animals that carry information to other members of the samespecies to tell them about the producer's sex or reproductive status. These experiments will provide the first clear description of theorganization and function of the extra-bulbar pathway. This research hasimportant implications for our understanding of the ways in which odorantinformation is converted into electrical signals in olfactory receptorcells, as well as the way odorant information is processed in the olfactorybulbs, potentially shedding light on the neural mechanisms underlying odorperception.