Polarization Sensitivity in the Crayfish Optic Lobe: Peripheral Contributions to Opponency and Directionally Selective Motion Detection. Glantz, Raymon M. Dept. Biochemistry and Cell Biology, Rice University, Houston, TX 77251.
APStracts 3:0152N, 1996.
SUMMARY AND CONCLUSIONS
1. Polarization sensitivity was examined in nonspiking interneurons, tangential cells, of the crayfish optic lobe. Stationary polarization sensitivity (PS) profiles were measured with pulses of illumination at fixed intensity and varied e-vector orientation (_). Dynamic polarization responsiveness was examined with a rotating polarizer. The dynamic response was assessed with variations in rotation velocity and direction and for variations in intensity. 2. Eighty percent of the cells tested were polarization sensitive. These were divided into two types. Type I exhibited PS magnitudes comparable to photoreceptors and lamina monopolar cells in the same species. Most Type I cells exhibited a directionally selective response to a rotating polarizer. 3. Type II cells exhibited PS magnitudes substantially higher than that observed in lamina neurons. These cells also revealed evidence for a polarization-opponency mechanism. 4. The results are interpreted in terms of a general hypothesis for polarization feature detection, based upon four principles: i) Most or all tangential cells are subject to inhibition; ii) The inhibitory pathway is polarization sensitive; iii) If _ max of the inhibitory input is similar to _ min of the excitatory input, then the inhibition forms the basis of a polarization-opponency mechanism; iv) If _ max of the inhibitory input is similar but not identical to _ max of the excitatory input, then the inhibitory input provides a basis for directionally selective polarization vision. 

Received 23 February 1996; accepted in final form 26 June 1996.
APS Manuscript Number J148-6.
Article publication pending J. Neurophysiol.
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 25 July 1996