Neurodevelopmental adaptations prime olfactory circuits for complex pheromonal communication in the clonal raider ant.

Project Summary Impaired social communication is a major feature of common neurodevelopmental disorders like autism spectrum disorder. Nevertheless, cellular mechanisms underlying the development of affected brain networks remain uncertain, despite the potential to inspire novel diagnostics and pharmacological interventions. Hence, this represents a key area of need in modern biomedical research. This career development proposal utilizes an emerging invertebrate model organism, the clonal raider ant, to investigate cellular mechanisms of neurodevelopment in olfactory brain circuits uniquely adapted for communication. Ants have evolved a remarkable capacity for chemical communication. Information is encoded by large arrays of pheromones exuded by dedicated exocrine glands and is received and processed by highly advanced olfactory systems. With approximately 500 olfactory glomeruli, the clonal raider ant antennal lobe (AL) is more complex than any other known insect and is evocative of the olfactory bulb in the brain of mammals (Drosophila have only ~50 AL glomeruli, for reference). Previous work in our lab suggests the evolution of sociality in ants may have coincided with unique neurodevelopmental logic in the AL supportive of this complexity. Over three aims, this project investigates early neuronal activity in pupal ant olfactory sensory neurons (OSNs) and its significance for the normal wiring of brain circuits in adults. First, Aim 1 utilizes GCaMP-expressing transgenic ants and in vivo two-photon microscopy to characterize spontaneous neuronal activity in the OSNs of clonal raider ant pupae. In Aim 2, OSN activity is manipulated throughout development using novel transgenic ant lines and the impact of these perturbations on olfactory circuit structure is investigated. In Aim 3, optogenetic tools are used to disrupt OSN activity during an isolated period of widespread synaptogenesis in mature ant pupae and the effect on neuropil volume is examined.