Long-term behavioral patterns across development are highly dynamic across and within developmental stages and temporally synchronized with the individual’s developmental clock. However, while long-term behavior may be shared by many individuals, reflected by stereotypic behavioral patterns, individuals within the same population may also show unique patterns of behavior that distinguish them from each other. This inter-individual variation in behavior exists even when animals are experiencing the same environment and have the same genotype. This phenomenon, which was characterized across multiple species, from invertebrates to humans, implies that there are additional non-genetic mechanisms that generate behavioral variation among individuals. Studying these novel sources of behavioral variation is crucial for the basic understanding of why individuals behave differently and may also shed light on sources of the emergence of mental disorders only in some individuals within the population. The general objectives of our project are: (1) understanding the underlying molecular differences across individuals, within the nervous system, that generate behavioral variation (2) exploring how these changes affect the nervous system’s function to affect behavioral diversity and (3) studying how different environments (like stress) affect variation in behavioral responses within the population. The results from these studies will uncover fundamental and conserved biological processes that generate behavioral diversity across development.
Overall, the action has successfully achieved its core scientific objectives by establishing a mechanistic and conceptual framework for understanding how behavioral individuality is generated, maintained, and reorganized across development. By combining large-scale longitudinal behavioral analysis with neuronal and environmental perturbations, as well as single-individual molecular profiling, the project has revealed how neuromodulatory processes interacts with developmental dynamics, to shape stable yet flexible individual differences in behavior. The tools, datasets, and conceptual advances developed through this action provide a lasting foundation for additional mechanistic studies and broadly enable the investigation of individuality across neural, developmental, and behavioral systems.
