NMDA receptors-dependent plasticity in the phototaxis preference behavior induced by visual deprivation in young and adult flies.

Adult mammals have experience-dependent plasticity in visual system, but it is unclear whether adult insects also have this plasticity after the critical period of visual development. Here, we have established a modified Y-maze apparatus for investigating experience-dependent plasticity in Drosophila. Using this setup we demonstrate that flies after the critical period have bidirectional modifications of the phototaxis preference behavior (PPB) induced by visual deprivation and experience: Visual deprivation decreases the preference of flies for visible light, while visual experience exerts the opposite effect. We also found an age-dependent PPB plasticity induced by visual deprivation. Molecular and cellular studies suggest that the N-methyl- d-aspartate receptors (NMDARs) mediate ocular dominance plasticity in visual cortex in mammals, but direct behavioral evidence is lacking. Here, we used the genetic approaches to demonstrate that NMDAR1, which is NMDARs subunit in Drosophila, can mediate PPB plasticity in young and adult flies. These findings provide direct behavioral evidence that NMDAR1 mediates PPB plasticity in Drosophila. Our results suggest that mammals and insects have analogous mechanisms for experience-dependent plasticity and its regulation by NMDAR signaling.