Fig. 5

a Images casted by neighboring fish on the retina of the focal fish are represented as a two-dimensional grid of retinal ganglion cells mapping the vertical height of the neighbors at different viewing angles Θ. b Retinal ganglion cells selectively project to two separate populations in visual areas: the ‘Rep’ population, which ultimately elicits turning responses away from the stimulated eye, and the ‘Att’ population, which elicits turning towards the stimulated eye at older ages. c The activity of all ganglion cells at a visual angle ϴ_i are combined by specific integrating units to represent the vertical height of the stimulus at that angle. These units relay their activity to an output population (brown triangles show activation, gray triangles represent inactive connections); we show three such example units, which represent the corresponding visual angles in (a). Active integrating units also stimulate an additional inhibitory population I (red), which suppresses the output population, and performs averaging of the inputs from the integrator units (see text). d, e. Each population in the visual areas can excite (green) and inhibit (red) motor centers on the ipsi and contralateral sides. At 7 dpf (d) responses are dominated by repulsion from the stimulated eye, while at 14 and 21 dpf (e) the balance of both the attractive and repulsive populations will determine the turning direction of the fish. Line thickness represents the strength of the excitation/inhibition, gray color represents inactive connections.