Social hierarchies can form within groups, leading to different costs and benefits for dominant and subordinate animals. In this sense, social status can greatly affect individual fish behaviour and reproductive physiology through interactions with conspecifics. Social learning has been suggested to shape the evolution of social behavior in cichlid fish, but there is not much evidence for other species. Considering that cognitive skills need to be transmitted and supported by neural systems for social systems to evolve, it is necessary to assess the effect of impaired sociality on social learning in other fish species. The Norton Laboratory has recently demonstrated that endothelin receptor aa (ednraa) zebrafish mutants display impaired social interactions compared to wild-type fish, including decreased shoaling and heightened aggression. Endothelins are 21 amino acid peptides that act as neurotransmitters and neuromodulators in the brain. Considering that ednraa mutants also show a difference in the size and location of AVP–positive neurons in the preoptic area, they constitute an ideal model to study the neuroendocrine regulation of social impairment.

This project will study the impact of impaired sociality upon social learning, and it will define which genes control social behaviour in the zebrafish brain. We will compare ednraa mutants and wild type fish to assess if impaired sociality decreases social learning and if reduced sociality is associated with differential expression in the Social Decision Making Network, an evolutionary conserved brain network regulating most social behaviours in vertebrates, including aggression, mating and parental care. This project will include protocols to assess social learning and also cutting-edge technology, such as RNA sequencing and transcriptomic analysis.