Abstract: The honeybee, Apis mellifera L., is one of the invertebrates that have been proven to have color vision through behavior tests. Previous study has shown that the chromatic information processing in the lobula of honeybee could be diverse with response patterns. Among those visual neurons, color opponent cells (COCs) have been thought the most important neurons for color discrimination. However, in the natural world, color vision of honeybee only expresses in luminant environment. The behavioral tests showed that bees performed color vision only above a certain intensities of light stimulus. Thus it is possible that there is a neural response threshold in the color opponent system. To reveal the existence of neural threshold, intracellular recording technique will be applied in this study. With intracellular recording technique applied on this project, it is possible to inject dye to the recorded COCs and to study the morphology of the cells. Responses of higher order visual interneurons, especially the COCs, to different light intensities of flashes will be recorded under dark-adapted to characterize the chromatic pattern of COC. The intensity-dependent phenomenon will be identified by this study, which can indicate that the neural response patterns were different dependent on the stimulus intensity and the neural sensitivities. Additionally, the response pattern of the COCs under light-adapted condition will be revealed by this study to demonstrate the signal processing of color vision in the compound eye system. It is very likely and expected that some neural modulation for the intensity-dependent phenomenon might play a key role for the COCs to deal with the complex light environment.
color opponent cell