Olfaction is decisively important for the control of many insect behaviors. Orientation toward hosts, feeding, egg-laying, aggregation, and courtship and mating in many species of insects -- including vectors of parasitic and infectious diseases and agricultural pests -- are strongly influenced or controlled by these antennal senses. Very little is known, however, about the processes in the insect central nervous system (CNS) through which olfactory information influences behavior and which might be exploitable for improved strategies of insect management. This research has as an ultimate goal the understanding and exploitation of central processes in olfaction and other antennal senses, first in the experimentally favorable """"""""model"""""""" insect Manduca sexta and eventually in medically and economically important (but experimentally less favorable) species, which are key determinants of harmful or otherwise important insect behaviors. Present knowledge of the structure and physiology of sensilla and their receptor cells in the antennae and other sensory organs of insects provides a basis for a detailed neurophysiological and structural study of neural pathways subserving olfaction and other antennal senses in the insect CNS. In this project, we plan to continue our established research effort aimed at revealing neural mechanisms of information processing in the insect brain, through which biologically meaningful odors as well as mechanosensory, humidity, and temperature stimuli detected by the antennae generate """"""""higher-order"""""""" neural signals that ultimately trigger or sustain significant behaviors. Our studies aim to trace the projections and connections of specific types of central neurons in the antennal-sensory pathway; to characterize by means of intracellular recording the electrophysiological responses of neurons in the antennal lobes of the brain to defined and biologically meaningful antennal stimuli; to analyze the processes of central integration of sensory information and the underlying synaptic organization and mechanisms in the antennal lobes; to probe for neuromodulatory mechanisms in the central olfactory pathway; to explore further the usefulness of 2-deoxyglucose radiochemical activity-labeling to map patterns of neural activity in the antennal sensory pathways in the CNS; and to pursue further our collaborative efforts to characterize the sex-pheromone system of Manduca, to unravel ultrastructurally the details of synpatic """"""""wiring"""""""" in the olfactory glomeruli of the antennal lobes, and to characterize fully the responsiveness of individual receptor cells in antennal olfactory sensilla.
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