Intracellular electrophysiological responses of photoreceptor cells in flies carrying ninaC^1015.4 in a ninaC⁵ background are abnormal. There is a small defect in adaptation, as indicated by the slightly smaller light-coincident spike relative to wild type. There is a delay in termination and an ensuing slow deactivation.

Flies carrying ninaC^717.3 in a ninaC⁵ background have a null electroretinogram phenotype and a retinal degeneration phenotype intermediate between wild-type and that of ninaC⁵ flies, at 25^oC. The ERG is wild-type at 18^oC. Retinal degeneration is severe at 29^oC.