Establishment of a transgenic strain for the whole brain calcium imaging in larval medaka fish (Oryzias latipes)

GCaMP-based calcium imaging is a powerful tool for investigating neural function in specific neurons. We generated transgenic (Tg) medaka strains expressing jGCaMP7s across extensive brain regions under the control of the gap43 promoter. Using these Tg larvae, calcium imaging successfully detected a tricaine-induced suppression of spontaneous neural activity and topographical visual responses in the optic tectum elicited by moving paramecia or optical fiber stimulation. These results indicate that our Tg medaka strains provide a versatile platform for investigating neural dynamics and their responses to various stimuli.