Our group investigates the multifaceted influence of light on mammals. How does the retina produce visual information? How is this information processed within the brain for functions that are as diverse as perception and the regulation of circadian rhythms? How is the visual system configured to the needs of different species? We pursue such questions quantitatively, applying electrophysiological and imaging techniques in vitro and in vivo. We go bottom up and top down in search of mechanisms at the molecular, cellular, and circuit levels that are especially vital to the animal. By making rigorous comparisons across levels, we seek to understand how increases in complexity produce gains in areas such as sensitivity, dynamic range, adaptability, and robustness.