Neurotransmitters appear to play critical roles during development of the nervous system in addition to their functions as signaling molecules in the mature brain. However, the neurogenic roles for these molecules have not been fully elucidated. These experiments will test the hypothesis that the neurotransmitter serotonin (5-HT) is a trophic factor critical for the normal development of central nervous system (CNS) circuitry in the model system Drosophila melanogaster. Changes in 5-HT levels during CNS development should affect the development of the neural circuitry, and therefore affect functioning of the mature CNS. Genetic and transgenic tools will be used to constitutively alter 5-HT levels to establish that both the normal circuitry and the function of the CNS are affected. Similar tools will be used to temporally and spatially disrupt normal neuronal 5-HT levels to separate the neurogenic role of 5-HT from its function as a modulator of different behaviors. This award will focus on the serotonergic fibers innervating the gut as well as the antennal lobes and mushroom bodies, since these fibers are limited in number and thus provide a simple system in which to assess changes in varicosities, arborizations, and cell number. The function of these circuits will be analyzed by assessing feeding and olfactory behaviors, which have been shown to be affected by altered neuronal 5-HT levels. These experiments will elucidate the neurogenic role of 5-HT in the developing gut and olfactory circuitry and establish the functional consequences of defects in this process. This research program addresses a critical biological question (development of CNS circuitry), and will generate numerous reagents that will be made available to the scientific community.
Activities to be carried out under this award will have a direct impact on scientific education and training. Several undergraduates have directly participated in NSF research projects from this laboratory; seven have been coauthors on papers, and have presented their work at scientific meetings. In addition, Dr. Neckameyer has also hosted high school teachers and students in her laboratory in order to teach the concepts and techniques used in her work.
