The response properties of retinula cells in the fly Calliphora erythrocephala as a function of the wavelength and polarization properties of visible and ultraviolet light

Abstract

Detailed functional response properties of the class (1–6) retinula cells in the insect Calliphora erythrocephela have been determined as a function of the wavelength of monochromatic light and polarization conditions over a six log unit range of light adaptation levels. These stimuli were produced as a small parallel beam that could combine various wavelengths in both the ultraviolet and visible regions whose polarization planes could be individually controlled. The wild type and white-eyed mutant were studied and shown to have no significant differences in their response properties. It was shown that previous tests using transient stimuli, large compared to the adaptation levels produced responses of high orders of nonlinearity and rapidly changing transient properties. In contrast, the use of white-noise tests did not cause changes in the basic cell properties as established by a given light adaptation condition. These tests accurately model the visual conditions of a wide and representative range of normal behavioral conditions and the model response data thus obtained can be directly correlated to important physiological tests for the same stabilized adaptation conditions. The simultaneous application of both visible and ultraviolet monochromatic light revealed a complex response interaction which changed the self response contribution of the ultraviolet light from that due only to ultraviolet light but had no effect on the visible light response. It also produced a mutual interaction. This effect was found to be the same for all members of the (1–6) class of cells when the light was unpolarized but varied for different members of the class for polarized light depending upon the relative angles of the E-vectors for the two types of light which in turn vary for different members of the six cell classes.