Processing of visual information in the insect retina.

The fly is presented as an example for visual information processing. It is shown that "simple" compound eyes of insects possess functions which are comparable with those of the complex lens eyes in higher vertebrates. The problems of coding of contrast, colour and polarized light are discussed. Temporal resolution of the visual system is characterized in terms of a transfer function and this reveals differences to vertebrates, but only in respect to the higher fusion frequency. Spatial coding of light informations is not very well understood but there is evidence for lateral inhibitory interactions, especially in the lamina. Thus we can conclude that the retina presents all premises at least for a simple shape and motion analysis in the fly's tiny brain.