Sensory circuits frequently integrate converging inputs while maintaining precise functional relationships between them. For example, in mammals with stereopsis, neurons at the first stages of binocular visual processing show a close alignment of receptive-field properties for each eye. Still, basic questions about the global wiring mechanisms that enable this functional alignment remain unanswered, including whether the addition of a second retinal input to an otherwise monocular neural circuit is sufficient for the emergence of these binocular properties. We addressed this question by inducing a de novo binocular retinal projection to the larval zebrafish optic tectum and examining recipient neuronal populations using in vivo two-photon calcium imaging. Notably, neurons in rewired tecta were predominantly binocular and showed matching direction selectivity for each eye. We found that a model based on local inhibitory circuitry that computes direction selectivity using the topographic structure of both retinal inputs can account for the emergence of this binocular feature.During sensory processing, information from several distinct sources often converges onto neural circuits that are responsible for the performance of novel computations. This kind of integrative processing can be unimodal, as with binocularity 1-5 , or multimodal, combining visual, auditory and somatosensory information [6][7][8] . Although integrative circuits have been well characterized, the global developmental rules underlying their coherent organization remain unclear.Binocular neural circuits are particularly well suited for the study of integrative processing because of their accessibility, the independence of each retina and the clearly defined stimulus space. The unique properties of these circuits were first described in a series of pioneering experiments in 1962 (ref. 1 ). From this and other studies, it is known that neurons in the first stages of binocular processing not only integrate visual information from both eyes, but that a majority of these neurons also show a marked alignment of receptive-field properties for each eye with respect to retinotopic position, direction and orientation selectivity 2-5 . In the case of directional tuning, this means that binocular neurons that are tuned to a particular direction of visual motion in one eye show selectivity to the same direction of motion in the other eye. A similar functional alignment is observed between