OEB Seminar Series

Benjamin de Bivort
Harvard University, Department of Organismic and Evolutionary Biology
“The Neurobiology of Individuality”

Abstract: Individuals often display conspicuously different patterns of behavior, even when they are very closely related genetically. These differences give rise to our sense of individuality, but what is their molecular and neurobiological basis? Individuals that are nominally genetically identical differ at various molecular and neurobiological levels: cell-to-cell variation in somatic genomes, cell-to-cell variation in expression patterns, individual-to-individual variation in neuronal morphology and physiology, and individual-to-individual variation in patterns of brain activity. It is unknown which of these levels is fundamentally causal of behavioral differences. To investigate this problem, we use the fruit fly Drosophila melanogaster, whose genetic toolkit allows the manipulation of each of these mechanistic levels, and whose rapid lifecycle and small size allows for high-throughput automation of behavioral assays. This latter point is crucial; identifying inter-individual behavioral differences requires high sample sizes both within and across individual animals. Automated behavioral characterization is at the heart of our research strategy. In every behavior examined, individual flies have individual behavioral preferences, and we have begun to identify both neural genes and circuits that control the degree of behavioral variability between individuals. Our recent efforts focus on three questions: 1) what computation is performed by circuits that regulate behavioral variability, 2) can we identify “engrams of individuality,” morphological or physiological correlates of individual behavioral biases, and 3) does behavioral variability reflect developmental stochasticity/decanalization, or a regulated, adaptive bet-hedging strategy to thrive in variable environments?