In the visual system different classes of retinal ganglion cell (RGC) respond to and convey qualitatively distinct information about the visual environment to the brain. From these parallel inputs the brain builds a complete and coherent representation of the visual scene and then generates appropriate behavioural responses. We are using the optic tectum of larval zebrafish as a model system to ask how the brain performs these functions and how the underlying circuitry develops. A prerequisite to understanding how visual information is processed by the tectum is a detailed description of the nature and organisation of visual inputs to the tectum. To describe both the functional properties and laminar organization of different types of RGC input to the tectum we have fused the synaptic vesicle protein, synaptophysin to the genetically encoded calcium sensor GCaMP3 (SyGCaMP3). We have generated a stable transgenic line of zebrafish that express SyGCaMP3 specifically in RGCs. By combining in vivo imaging of SyGCaMP3 responses with patterned visual stimulation we can record stimulus-evoked calcium influx at identified presynaptic terminals in the brain. We are also able to assign RGC terminals with defined response properties to defined locations within the tectum. Using this approach we are building a map of motion-sensitive inputs to the tectum. By performing these experiments at different developmental stages we can ask how this map develops and how the functional properties of RGCs themselves emerge. We hope that this information will serve as a useful point of reference for understanding how visual information is processed within the tectum.