Uncovering the basis of behavioral individuality across developmental time-scales

ended

A fundamental question in biology is why different individuals show different behaviors. While individuality in behavior is usually explained by genetic heterogeneity or differences in environmental exposures, more recent studies have shown that stable behavioral variation is also observed among isogenic individuals that were raised in the same environment. However, this important and potentially conserved epigenetic source of individual-to-individual behavioral variation remains largely unexplored. I have recently developed a novel imaging setup, using C. elegans, that allowed for the first time to study behavioral individuality across the full development time of animals, at high spatiotemporal resolution and under tightly controlled environmental conditions (Stern et al. Cell 2017). By using this unique system I found that isogenic animals show long-term behavioral individuality that persists across all developmental stages, and was dependent on specific neuromodulators. In this proposal I suggest to study how behavioral individuality emerges across development from non-genetic differences among individuals. In particular, I plan to (i) identify neuronal circuits and variations therein that lead to different behavioral states among individuals by combining my established methods for longitudinal behavioral quantifications with cutting-edge neuronal imaging and molecular techniques; (ii) study the role of conserved epigenetic mechanisms in generating stable neuronal and behavioral variations by integrating high-throughput gene-expression, neuronal, and behavioral analyses in single animals; and (iii) explore how stressful conditions affect behavioral individuality. I hypothesize that stress may enhance variation as a population-level mechanism to diversify risk in the face of complex or unpredictable conditions. The proposed research will shed light on novel processes that establish and maintain inter-individual diversity in neuronal and behavioral patterns.