Dietary tuning of infant social interactions

The ability to deal with a broad array of social behaviors is fundamental for survival, health and reproduction in our society. Although we are constantly involved in social interactions, many elementary questions remain unanswered: How are social behavior decisions made on a brain circuit level? Which factors are processed and integrated into the neuronal network to modulate decision making? Nutrition and social behavior are closely intertwined from the beginning of our lives: communication of nutritional need is our very first social interaction, laying the foundation for a healthy life. Surprisingly little is known about how nutritional fluctuations during brain development affect the organization of cells in the brain and influence social interactions. Diseases like ADHD (attention deficit hyperactivity disorder) and autism spectrum disorder share impaired social function as a prominent feature and depict the effects of aberrant neurodevelopment. Studying how infant diet is linked to social behavior is strenuous in mammalian infants: pup development largely takes place in the womb, they are constantly dependent on their mothers, and it is difficult to observe and manipulate the brain during development. We will overcome current limitations by adopting the comparably simple brain from poison frogs as a model system. Adult females of the Mimetic poison frog Ranitomeya imitator provide parental care by provisioning unfertilized eggs to the developing offspring. Nutritional need primes tadpole social interactions and can manifest in two distinct behaviors: displaying a conspicuous begging behavior to a caregiver or displaying aggressive behavior towards conspecific larvae. Using the behavioral repertoire and the possibility to genetically manipulate the transparent R. imitator tadpoles, we will fill the knowledge gap of how nutrition is linked to infant social interactions. We will combine the most recent technologies in neuroscience and genetics to track the cellular and molecular mechanisms regulating nutritional state and related social interactions through the following aims: (1) Characterize how diet affects the organization and function of neuronal populations that evaluate nutritional state. (2) Map and functionally interrogate the neuronal circuits underlying infant social behavior in a nutrition-tuned framework. The proposed project will be the first study to evaluate how nutrition tunes neonate affiliative and aggressive social interactions. Our findings will contribute to the understanding of diet associated behavioral conditions in infants.