Role of G protein-coupled receptor 139 in cognitive functions in zebrafish

G protein Coupled Receptor 139 (GPR139) is an evolutionarily conserved orphan receptor involved in controlling motivation and reward. In the zebrafish, GPR139 is exclusively expressed in the ventral habenula, a region of the brain that mediates aversive responses. By combining immunofluorescence technique, behavior, and Ca2+ imaging recordings in slice culture, we demonstrate that GPR139 signalling in the habenula plays a differential role in multiple phases of fear conditioning via modulation of habenula neural activities in the zebrafish