A combination of behavioral and neurophysiological approaches will be used to study the mechanisms that control the wiring of connections between neurons in the brain, and how specifically this wiring contributes to the ability of moths and other animals to process and discriminate amongst different odor mixtures. The work will specifically address questions related to plasticity in the olfactory system, using several moth species including the corn earworm and the tobacco budworm. The investigators will transplant antennal imaginal discs between males of different moth species to study the interactions of sensory nerve cells with central neuronal types in the olfactory structures of the insect brain. Previous studies have shown that challenging the insect antennal lobe using this transplantation technique results in the development of unexpected sensory input, including re-routing of neurons that arborize in a novel fashion in the olfactory area of the brain, which results in changes in functional interpretation of sensory inputs. The results indicate that there is considerable plasticity in the mechanisms regulating the identity, guidance and targeting of sensory and central neuronal pathways, which can result in changes in the neural processing and behavioral discrimination of odor quality. The current award will address in part the specification of central olfactory projection neurons with respect to growth and development in defined spatial locations in the antennal lobe. The investigators will also examine the functional significance of novel projection neurons with respect to their output. The combination of behavioral and neurophysiological approaches to be used will provide generally applicable insights into the mechanisms that control the wiring of connections between neurons in the brain. This approach is of importance because it involves a natural chemical communication system, containing relevant odors in the life-history of the insects, which can be analyzed with very sensitive behavioral assays and established neuroanatomical and physiological techniques. The work is a collaborative partnership between investigators at Cornell University and the University of Utah will involve the training of a variety of personnel from high school students to undergraduates and visiting scientists who will benefit from exposure to an integrative, collaborative research program. Results from these experiments will be incorporated into classroom teaching and general public outreach activities.
