We will summarize and discuss our visual experiments reported in five publications and at the last six SfN meetings. These experiments return to first principles, viewing the retina as a transducer that converts light energy into time-locked optic nerve impulses that can be followed from retina to cortex. Using an implanted rat model with LEDs glued to the skull, we delivered flashes (controlled for luminance and duration) to the animal when awake or asleep and while light- or dark-adapted. The stimulus-locked electrical responses were recorded through small stainless steel electrodes implanted at cornea, chiasm, and cortex. Our 2003 SfN report used human behavioral studies to test, validate, and extend conclusions based on rat data. The principal findings: 1. Visual stimuli invariably generate rat and human optic nerve volleys that last about 300 ms, which indicates the mammlian retina normally converts all the information acquired during a flash or fixation, however rich or poor that information may be, ...