Divergent outer retinal circuits drive image and non-image visual behaviors

Image- and non-image-forming vision are essential for animal behavior. Here we use genetically modified mouse lines to examine retinal circuits driving image- and non-image-functions. We describe the outer retinal circuits underlying the pupillary light response (PLR) and circadian photoentrainment, two non-image-forming behaviors. Rods and cones signal light increments and decrements through the ON and OFF pathways, respectively. We find that the OFF pathway drives image-forming vision but cannot drive circadian photoentrainment or the PLR. Cone light responses drive image formation but fail to drive the PLR. At photopic levels, rods use the primary and secondary rod pathways to drive the PLR, whereas at the scotopic and mesopic levels, rods use the primary pathway to drive the PLR, and the secondary pathway is insufficient. Circuit dynamics allow rod ON pathways to drive two non-image-forming behaviors across a wide range of light intensities, whereas the OFF pathway is potentially restricted to image formation.

Automated summary

Image and non-image forming vision play important roles in animal behavior. This study used genetically modified mouse lines to investigate the retinal circuits involved in driving these two types of vision. The results showed that the OFF pathway is responsible for image formation, while the ON pathway is involved in non-image-forming behaviors such as the pupillary light response and circadian photoentrainment. Cone cells contribute to image formation, but do not drive the pupillary light response. Rod cells use different pathways to drive the pupillary light response depending on the light intensity.